One funny thing about ensemble shows is that you're always going to have those moments where you suddenly say "Hey! I know that guy/girl! He/She was on....". With Heroes though I think I have that expression on my face permanently and so want to go over the list of actors and their previous shows/movies/music videos.

Milo Ventimiglia (Peter): Jess in 'Gilmore Girls'

Adrian Pasdar (Nathan): one of the bumbling policemen in the Dixie Chicks' music video 'Goodbye Earl'

Ali Larter (Niki): Final Destination (I & II), Legally Blonde

Greg Grunberg (Matt): Felicity, Alias

Leonard Roberts (D.L.): Riley's military buddy in 'Buffy the Vampire Slayer'

Eric Roberts (Thompson aka Mr. Bennet's work 'buddy'): in The Killers 'Mr. Brightside' and Mariah Carey's 'We Belong Together' music videos

Clea DuVall (Audrey Hanson ): Loads of movies, including 'Girl, Interrupted', 'But I'm A Cheerleader', and 'The Faculty'

*Of course, this is just off the top of my head and without the help of imdb so I'm sure I'm forgetting loads. Who else has been in what, that you know of?*

Oh and "Charlie" in Heroes also plays "Charlie" in Ugly Betty. Not a normal nickname for females and yet the same actress plays two Charlies at the same time? Odd!