Some people have mentioned Gil Grissom on "CSI: Crime Scene Investigation" (the Las Vegas one) as a possible Aspie. He has unusual interests (bugs, riding on roller coasters) and is alone a lot; also people who have seen the show more than I have say he has trouble interacting with his employees, or is "unempathetic" towards them or something. (I've seen a couple examples of this, but since I haven't that many of the shows, can't say for sure. I know I've had bosses like him and I just thought it was a management style.) He is always very empathetic towards anyone considered "different" by society.
They have also mentioned Sara Sidle, another character on the same show (and now Grissom's love interest) as a possible Aspie: Struggles with relationships with her co-workers and men, has bad posture (people keep thinking she's pregnant because of the way she stands with her stomach stickng out: personally it's probably the actor who plays her who stands this way all the time, not only when she's playing Sara, and she's probably not AS), in her backstory it said she was into her studies all the time as a kid and never had friends until college. She also will kind of blurt out when she's telling someone their relative died, such as on the last episode if anyone watches that show. However, I think the backstory on her is that she saw one of her parents kill the other, and that before that the parents were very dysfunctional, so the writers may be thinking that someone who went though all this might have interaction problems and may not be thinking of AS.
I've also heard a character on "Law and Order: Criminal Intent" played by Vincent D'Onofrio (spelling?) seemed Aspie to some people, but I've never seen it so I can't tell.
Ryan Wolfe on "CSI Miami" might be as well as he has admitted OCD tendencies and has trouble getting along with his co-workers; it's hard to tell though if his trouble is just that he wants to get ahead really bad and is stepping on peoples' toes, or if he really wants to not hurt people but does anyway. Anyway, everyone on the show is written to always get along very well with everyone else, except for Wolfe; he sticks out like a sore thumb and people on the IMDb board for this show are always complaining about him. He also seems naive with women.
Also, that one family on "Third Rock from the Sun".
There's a recurring Aspie on "Boston Legal" but he's diagnosed.