79. Linda Cardellini
Age (circa 2009): 34
Her stint as a busty Velma Dinkley in Scooby Doo aside, the former ER star has scored numerous cool points throughout her career with roles that paint her as a funny, cute, down-to-earth chick. To wit: her genius-turned-freak in Judd Apatow's Freaks and Geeks.
We were ready to drop to one knee after watching her do karaoke to "Push It" in Grandma's Boy.