I was seriously disappointed by genV Pokemon, they looked worse than the johto ones, and the Johto ones were just weird, Gen V is like UGH! Regardless, I play Black. My least favorite pokemon is... hate it so much I forgot its name. Oh yeah, Mr. Mime. ITS A MIME.
Gen V pokemon look totally unattractive to me, that's why I have given my game away and have stuck with HG. To me, there is no pokemon in generation IV that is ugly or unattractive, the closest ones to that would be my disliking of Wynaut, or whatever its name is, Mr. Mime, and Voltorb, but really, in the end they aren't that bad.