Those pictures don't do Kristin Kreuk justice, but I would vote Erica Durance anyway.
supergirl gets my vote:
I'm glad someone finally posted a pic of her, saved me the search time.
She's easily my favorite fuckette on the show.
The only other thing I'll add is that every person on this show is always well built, lean, toned. Every single one of them, no one is even remotely overweight, the guys are all ripped (And subsequently always shaved), the girls always have nice tits and tight abs.
And I'm not just talking about the main characters, even the extras are like that.
Aye there's much better pictures of her on the way.