Yeah Gto made me laugh pretty much, I suggest you get yourself Love Hina, Onegai sensei, Vanderd, Chobits... Personaly the best anime I'we ever seen is One piece, it has more than 335 episodes out and there is still no sign of ending. It's about a boy who wants to become the king of pirates but to do so he needs to find a crew and fint the greatest treasure of all - One piece! The world of one piece is fictional and most of the time it is funny but it you can learn a great deal from it if you compare it to the real life. You can also try Naruto or Bleach. Altough if you're 21 than maybe not all of these are suited for you since one piece, naruto, bleach are kinda childish.
I liked it, hope you will too.