Gintama (the manga for this is my favorite manga)
http://www.animefushigi.com/Gintama/
One Piece
http://www.animeseason.com/one-piece/
However, there are alot of other anime I've watched that I can recommend for you like
Soul Eater (I wish I could put this in my top three. But then it'd be a top four. Are "top fours" normal?)
Clannad
07-Ghost
Death Note
D. Gray-Man
Rurouni Kenshin
Full Metal Alchemist (Hagane no Renkinjustsushi)
All the above anime can be watched at animeseason.com.
hope this helps! I've included a range of genres because you didn't say which you liked =] all of these are manga/anime that I've read/watched and really liked ^.^