Pros + Easily the strongest auto-attack in the entire game +Can build bruiser and still have the damage of an assassin + Ranged and tanky, can absolutely destroy most melee tops + Has tons of CC to knock and pull around people + Near impossible to turret-dive + Lategame becomes a freak of nature and will hit for 800-1400 consistently. Thresh has a tough start, but if you can get him to level 9 without trying to be a hero, 9 times out of 10 you've officially won your lane. His AD scaling on his Q is insane, and because of it he does hybrid damage, which most likely will get past whatever your opponent is stacking to coutner your bursty auto-attacks.

Cons - Weak earlygame - Champions with charges (Xin, Wukong, Irelia) can give him a hard time early on - Dosen't hit for insane amounts until level 9 - Not great at killing towers - Need to collect souls for maximum damage, and by proxy, dunkage - Attack speed not very viable on him As much of a monster he is mid/lategame, Thresh has a tough time in his earlier levels, although if you don't get too aggressive and ward the river, you shouldn't have too many problems.

Bloodthirster. You get 300 (100 Physical, 200 Magic) damage total off of this item, and a bit of lifesteal to boot. I normally grab 2 on Thresh by lategame, for a boost of 600 damage to his autoattacks (with full windup, without it should still hit for about 400).

Last Whisper & Void Staff real Dunkmasters do what they do for the ladies. Ladies love penetration. It also makes all that armor and MR the other team is stacking nigh useless. But its mostly for the ladies.

Frozen Mallet is a Dunkmaster's best friend. Tankiness + ability to smack down for extended periods of time. With the Mallet you'll be slammin' anyones jam who dares to cross your path. It also makes you a much scarier presence in teamfights, and with your CC will make it hard as hell to get away.

Mercury's Treads is a very solid choice for Thresh, mainly because of the tenacity and the MR, which he desperately needs.

All items are subject to change, and a Mercurial Scimitar is an AMAZING alternative to a second Bloodthirster.

OTHER VIABLE BOOTS:

Ninja Tabi is a great choice against a team with mostly AD. You are already going to have that nice tasty soul armor, but -10% damage from autoattacks makes an AD Yi cry.

Mobility Boots if your lane partner is roaming, or if you are bold enough to take Thresh mid (Which this build also works quite well with) and you want to be able to gank other lanes easier.

Sustain, sustain, sustain! Due to his range, an early Vampiric Scepter makes Thresh near immovable if you are smart and freeze your lane near your turret, harrassing the enemy top whenever he/she gets within smacking distance. Most tops are melee, and even if they charge you, you should be close enough to your turret to drag them right in. Once you start harvesting souls (And get about 20 or so), you will notice the opposing top doing slightly less damage to you, and you slightly more. Thresh is a great top because he gains armor and damage the longer he farms, while the opposing champion only gets gold until he returns to base. Farm religously (unless your team needs you elsewhere) until you get to about level 9, then try and make efforts to get their turret down. Once you do so, time to roam as a fed Thresh and slam some mad dunks!

You fill a bizarre role that meets in the middle of assassin and tank. You hit for absolutely unbelievable damage once you've hit level 9, so make sure to direct that damage where it is needed. Namely, enemy carries and squishies. A lategame dunkmaster should be able to 2-3 hit an ADC or most AP mids so take full advantage of your completely broken kit. If you get in a 1v1 with the ADC, dont worry! You've been building armor the entire game along with AP (The souls also add extra damage to your autoattacks!) So 2-3 seconds later, the ADC should be running like crazy after flashing or be dead.

You can solo baron at max level after your second Bloodthirster and Last Whisper(should have both bloodthirsters stacked and have about 330 damage minimum). I would NOT recommend doing so unless the other team is dead and the rest of your team is pushing (But not if you being there could mean you win).

EDIT: Cloth Armor and 5 Health Potions can be used to compensate rather well against most of these

Xin Zhao's dash and knockup will absolutely demolish you earlygame. Also, if he manages to get kills on you, then a fed Xin Zhao is a problem for everyone.

Wukongs combo dashes to you and lowers your armor, all while smacking you around. His ult is also a knockup, which isnt very much fun for Thresh.

****ing nerf Irelia.

Garen can get rid of your slows really easy, and yells "DEMACIA!" a lot. Neither signal fun times for you if you are anywhere but under your turret.

Kayle is ranged. You are ranged. Half your viability goes away when you're trading every hit instead of harassing. Not to mention Kayle has a heal, and you don't.

Rengar can dwell in bushes, out of sight, and just jump ya and combo half your health away. Again, if you lose half your viability, you are more or less screwed.

Kha'Zix does lots of damage, and although souls give you armor, he can jump you the second you hit half hp and burst you down.

Thresh is a very high skill cap top that can carry games and can straight up dunk people for massive if not outrageous(inb4 Taric) damage. It takes a ton of practice with him to get good at top laning, but once you've gotten practiced and experienced, Thresh is an outstanding top with very few counters.