I couldn't pick just one, to be honest. My usual comic book references aside, I'd have to pick at least 2 - NCIS: Los Angeles, where I'd probably play the standard guy who gets
And then there's a series that's been around for well over 10 years - Stargate - both Sg-1 and Atlantis are in syndication and while I didn't get into Universe, I'd want to be in the straight-to-DVD Stargate movies that features Mitchell, Daniel, Teal'c, Carter and - occasionally - Jack as one of the members of SG-3. Maybe a Lieutenant for a rank, if I wasn't allotted the rank of Captain.
I do have some acting experience under my belt, so I'm fairly positive either role could work.