Alyson Hannigan

There may never be another actress quite like Alyson Hannigan, who has encompassed three big roles, two on television shows, and one big one in film. She got her big break in film with the series American Pie, where she uttered one of the most quotable lines in the entire genre of teen comedies, “One time at band camp."

Her big television shows were that of Buffy The Vampire Slayer, where she played the title character’s best friend, Willow Rosenberg. She gained main exposure from this role, which led to other roles, specifically the role of Lily Aldrin, on How I Met Your Mother, arguably her biggest role to date. She will play this role through the end of the series, which ends in 2014.