I found this site a while ago, and while it may not interest you, I think it's very well layed out. Either go by series or by voice actor, and for each seiyuu it lists all (or many of) their roles. Very interesting to compare and make connections between roles and characters etc. Certainly I've enjoyed having a look.
http://www.seiyuu.info/extendedlisting.php?list=anime
I don't have a personal favourite though.