For most people these days there is only 1 deck worth running, the one with its own ROTA, Demise, Cylinder, Zombie Master, Breaker etc. I'm on about Lightsworn obviously, and have been running it for the past few months, taking a break (or a risk that blew up in my face) every so often to try out something new.
As everybody that's run the deck will know, it tends to fall flat on its face every so often, usually after milling most of its 'outs' or not milling any Necro Gardnas. During this time I've tried out various things with the deck in order to make it safer to run and have come to a conclusion; 40 cards is the way to go.
Here's the deck I've been running at locals for the past few weeks, going undefeated in the process:
2 Judgment Dragon
2 Celestia, Lightsworn Angel
3 Necro Gardna
1 Plaguespreader Zombie
1 Gorz the Emissary of Darkness
3 Lumina, Lightsworn Summoner
2 Lyla, Lightsworn Sorceress
2 Wulf, Lightsworn Beast
1 Garoth, Lightsworn Warrior
1 Ehren, Lightsworn Monk
1 Aurkus, Lightsworn Druid
1 Ryko, Lightsworn Hunter
3 Charge of the Light Brigade
3 Solar Recharge
2 Gold Sarcophagus
1 Heavy Storm
1 Mystical Space Typhoon
1 Foolish Burial
2 Threatening Roar
2 Beckoning Light
1 Mirror Force
1 Torrential Tribute
Extra Deck: 15
2 Stardust Dragon
1 Colossal Fighter
1 Thought Ruler Archfiend
1 Red Dragon Archfiend
1 Avenging Knight Parshath
1 Black Rose Dragon
1 Ancient Fairy Dragon
1 Goyo Guardian
1 Gaia Knight, the Force of Earth
1 Iron Chain Dragon
1 Tempest Magician
2 Magical Android
1 Armory Arm
Side Deck: 15
2 Kycoo the Ghost Destroyer
1 Shiny Black "C"
1 Aurkus, Lightsworn Druid
2 Lightning Vortex
1 Monster Reincarnation
1 Brain Control
3 Royal Decree
2 Bottomless Trap Hole
2 Fairy Wind
The deck functions just like any other Lightsworn deck; fill up the Graveyard and abuse its reverse-toolbox capabilities before finishing off with one of the most feared Dragons in the game's history. The problem with this is that the method of filling up the Graveyard is largely uncontrollable.
People have also been using the fact that the deck can draw/mill cards so fast as justification for running 42, 43, even 44 cards. While upping the deck count by 1-2 cards won't hurt the odds of 'drawing/milling X' too much, the decktype's got enough control problems as it is without having to fight against reduced odds of success. This is why I run 40 in Lightsworn now, I want the deck to 'go off' every game, and if it doesn't I don't want to be waiting 1-2 more turns for that 'swing card' than I have to.
Up until a few weeks ago I was in the 42 camp, dropping the odd match here or there and not worrying about it too much. The things is, since I play at very small locals (8-12 players on average, it's a shame that the numbers at both locals are only about half of what they were last year) there's less rounds of Swiss. In Limerick you have to go x-0 over 4 rounds to win, as there's no playoff. In Cork, x-1 will take you to top 4, but that 'one match loss' could come just as easily in the playoffs as it could during Swiss. Because of my competitive nature (though not as overly-competitive and ruthless as I was in 2008) I aim to win every locals I attend, and to go x-2 or better at larger tournaments. That means cutting out any controllable losses I can, and leaving the rest down to fate.
Anyways, in order to cut down to 40 I had to strip the deck down to its core and build it up to 40, rather than down. When I did this I had 31 cards in the deck and from there I rounded out the monsters first. In order to get out Judgment Dragon you need 4 different Lightsworn monsters in the grave as soon as possible. Most of the Lightsworn decks I saw and ran in the past only had about 6 different names in their deck, so the odds of milling 4 in 2 turns (you should be able to drop JD on your third turn if the deck's going according to plan) are a lot lower than you think. Upping it to 8 means I have more uses for Charge, and a greater chance of getting JD out earlier.
First in after the 31 was Ryko, since it creates so many mind games to exploit. Any set monster could be the Ryko, and until it's safely in the Graveyard, your opponent will usually play more conservatively whenever you set a monster. Next up was Ehren which I added purely because this is a locals deck, and as such isn't designed to win an SJC (ie: you're not going to face as many mirror-matches and Tier 1 decks/players). Players are usually more conservative at my locals regardless, and Ehren can take advantage of that. The final monster to make the cut was Gorz. Given that the deck only runs 6 traps (all semi-chainable at the very least) this was a no-brainer. 2700 attack coming out of nowhere is dangerous enough on its own, and the token can have its uses too. I like the fact that it's LIGHT, and even used Honest to boost it up enough to win in one of the finals recently.
The spell lineup is pretty standard for the most part. 3 Charge and Recharge are staples, as is the Heavy Storm. I never feel safe with just one backrow clearer (Celestia, Lyla and JD force you to commit to the field to pop cards) in any deck so I added MST, a card that taught me so much about the game when I was a novice. Foolish Burial allows me to manually take control of the Graveyard a little, either to get that crucial Plaguespreader in there, bring out a free beatstick (Wulf) or set up a larger play. I decided not to main Brain Control despite how much I like the card (it wins games) as it doesn't directly contribute to what I'm trying to do. There are matchups where it can be handy though, hence why it's still sided.
As for the traps, I wanted to have enough to be able to open with at least 1 every game so I went with 6; 2 Roar, 2 Beckoning, 1 Mirror, 1 TT. The Roars are in there because I don't ever feel safe from attacks with just Gardnas and Honests as they can be played around. Mirror Force is mained as an alternative to the third Roar because sometimes it's just plain better. Most players don't see it mained in Lightsworn decks either so it can cause some upsets Game 1 and force caution in Games 2 and 3. Torrential's inclusion is pretty obvious, plus it's one of my personal staples in every deck anyways. 2 Beckonings also make sense and finish off the deck. I used to go 2 Beckoning, 1 Reincarnation, but every card counts in a Lightsworn deck, and you don't want to have to commit when things can go wrong so easily (Crow, Solemn, etc.). Beckoning can also have some nifty tricks up its sleeve when combined with Honest and your opponent's Battle Phase.
The Extra Deck is a massively underrated portion of the Lightsworn deck, just because it's used so rarely. What people don't realise is that it makes the mained Plaguespreader one of your most versatile and explosive cards in the deck. The right Synchro Summon at the right time can wreck an opponent so it's important not to waste it 'just because I can Goyo his whatever this turn'. I've tried to vary it as much as possible, running 13 different Synchros. I kept 2 Stardust in there because I never feel happy with having just 1, and 2 Android incase I get the opportunity to tune up with 2 Luminas over the course of the duel. This versatility has won me a lot of games, with Tempest Magician being my favourite of the lot (it was my only out in one of my games in Limerick, as I was staring down a field of JD/DaD/Sorcerer. I also got to burn a Magical Citadel deck for 7,500 in Cork when I was about to deck out).
The side doesn't play too much of a role at locals, since the main is strong enough to overcome most of my expected matchups. Light-Imprisoning Mirror is still a major weakness to the deck if it's flipped early enough so the 3 Decrees are in there to take care of that. If I need what traps I've already mained (or need to side in Bottomlesses while also dealing with Light-Mirror) I tend to go with Fairy Wind. It's more reactive than Decree at the same time, and can help against Dimensional Fissure and various other threats as well (I would have lost to a Wave-Motion Cannon burn deck in the Cork finals 2 weeks ago if it wasn't for my Fairy Winds. The deck beat everything else that day but me.). Bottomless Trap Holes would be mained if I didn't feel I needed to main Roars, they usually swap in though if I'm playing against a less aggressive deck than usual.
Monster Reincarnation's there for when I side in Decrees (which would lock out my own Beckonings) or for those matchups where I'm really gonna need JD and Celestia (like that Burn matchup I was on about). Vortex is my choice card for when I need more proactive monster removal, or have to clear large fields quickly (Blackwing and the mirror mainly). I was maining a single copy ever since I saw how good it was in the mirror at UkayPro Championships, but it wasn't essential enough for me to up the deck to 41 or keep it in at 40.
Kycoo's a great card these days, shutting down the mirror match and wrecking Graveyard-based decks in general. It's also a nice big beatstick for the Stun matchup. The second Aurkus is a Side Deck staple and a no-brainer considering how many Monarch matchups there are at local level (great card against Blackwings and Gladiators as well, mind). Final card (Card #70 if you will) is Shiny Black "C", which I stuck in because of all the love that Synchros get in Limerick, and one particular deck that can explode like TeleDaD when given a chance.
So there you have it, that's what I've been going with for the past month or so and it's served me well. I also employed a simple philosophy to go along with it, but in all fairness it's just a bit of common sense and self-control:
1] Fill the grave till you've got 4 different Lightsworn monsters (this includes the ones on the field).
2] Once that's done stop milling. You want to be able to draw into everything in your deck now (bar Wulf).
3] Hold back on the Judgment Dragon until you feel that they've no outs to it over 2 turns. Make them waste their removal on your Luminas etc. which will put you up to 4 sworn in grave.
4] Hold back on your (usually) single Synchro Summon until you absolutely need it.
That's how things should play out when you draw a stable hand. If you open with a Beckoning feel free to go all-out to up the odds of milling a JD or two. Some games will just play themselves out as everything falls into place and some games will force you to go into 'crisis management mode', where the price for sticking to the plan above is losing the game.
The deck isn't spectacular or ground-breaking, just a solid locals deck with a common-sense approach. Feel free to copy it and tweak it to your locals meta. If you're planning on taking it to a Regionals or SJC, remember that this deck isn't designed to win those, but some of the card choices may apply to your playstyle and the expected meta.