Twitch or Alistar

champs like yi, and trynd are better at BDing. i'd agree with alistar, i also think blitz is a good pusher. pop w, spam e, and the tower is down pretty quick. use the (active) ult to clear out enemy creeps if needed.

Any of these heroes + Taric

I've seen Warwicks that ripped through towers pretty well.

Basically, anything built for autoattack dps. The more your damage is loaded onto abilities, the worse you'll do against a tower.

Edit: Mundo can attack a tower and slaughter a wave of enemy creeps at the same time. Nice if you're not yet at the point where you can just rip the tower down.

Granted i havent been playing for a long time, but in my opinion (and i am a bit biased seeing as he is my favourite of all times) Singed is a good lane pusher, and thus a good turret destroyer...the gas kills just any wave in a matter of seconds, thus letting the tower under constant attack from your own waves of creeps. While that may not count as a great tower "slayer" per se, it can seriously maul down towers right from early game. End game since team play is really kicking in, yes it might not be as good a method though.

I think Tristana deserves a mention here. She's not spectacular at pushing the creeps, but once you get some items, Rapid Fire takes down towers like they're nothing. I think I've single-handedly taken towers from full to demolished in a single Rapid Fire volley at the end of long games.

i get towers down in 5-7 secs w/ yi's ult, the best tower killer ever
XD

Early game, Zilean. He can easily kill all the enemy minions guarding a tower and get a tower down very early. Late game, same thing, but just about anyone else will do it better.