One of the biggest surprises for me was the variety found in the new characters created for Street Fighter EX.  Too bad that we haven't seen them work their way into Street Fighter proper (or at least into Marvel/Capcom).  Skullomania is, without a doubt, my favorite.

Everyone says Skullomania, and I was going to say Skullomania, because he is the only one whose name I can recall. I'd actually love some of the Street Fighter 3 characters to appear in another game. I'd say a main series entry is more important the the EX games.
Actually, I'd just like more consistency in character rosters.