They do have moments of brilliance--particularly Icons. That is the best show that they do on G4, at least when they focus on something game related. Lately they've been focusing on Michelle Rodrigues and Jamie Kennedy (wtf?), but their previous ones that were related to games were absolutely brilliant.

Cinematech is pretty interesting to watch as well, and Xplay is another quality show.
Some of the other shows are not original (as in, not made by G4)--Star Trek, Fastlane, Braniac, etc... so they don't really count.