Sarah Walker (Yvonne Strahovski), Chuck
No question: The blonde bombshell is the sexiest super agent since Jennifer Garner. Though Sarah can be warm and kind, there's a ruthless killer just waiting to be unleashed. What's worse for her targets is that her many sexy costumes — Princess Leia! — leave you slack-jawed so you won't even realize there's a giant knife barely concealed under that slit in her dress. At least most of her kills probably died with smiles on their faces.