I have an external USB tuner made by pinnacle systems. I used it in the dorms with my laptop. The software that came with it was a little crude. There was a very noticable lag, so I couldn't really play any console games on it. The audio is mono, and must be hooked up externally (doesn't use wav audio over the usb connection) to your line in with a 1/8" connector.
Pinnacle TV USB
Pros: Small, space-saving television on your pc
Image quality is decent (but noticably grainier than traditional TV).
Cheaper than traditional TV
Cons: Audio quality is poor, extra connection is necessary
Kinda ugly looking
LAG!!!
Image quality is not as good as traditional TV.