I personally haven't much anime,
though xbox650 on the other hand has seen a lot.
I have seen the Dragon Ball Z series. (Well the Kai version that is, which is the same thing but with a lot of filler stuff cut out.)
It's quite clean, really the only thing it has is violence.
... I can't think of anything else. XD
Xbox650 did recommend two sports anime to me,
a short soccer themed one called Giant Killer,
and a football themed one called Eyeshield 21.
Gundam should also be a clean series.
Another interesting series I've started watching is Sword Art Online. Only an episode in, but there isn't much bad stuff so far. BTW, I found a site called Crunchyroll that allows users to watch anime for free. It's basically like Netflix for anime/manga and it's not illegal.
Ah, I haven't seen it, but unfortunately I hear it all goes down hill part way through.