In my opinion the following animes are really really good
One Piece (Ongoing)
Naruto (Ongoing)
Ranma 1/2 (Finished)
Fairy Tail (Ongoing)
Avatar: The last Airbender (finished)
Avatar: The legend of Korra (continues at the end of 2012-beginning of 2013)
Dragonball (Finished)
Dragonball Z (Finished)
Dragonball Hoshi (starts in 2013 but I don't know if it will be good as DB and DBZ yet)