Tradeshow coverage is amazing. Interviews with developers are top notch. There are a few exclusives here and there that are pretty good (like the Id interview I referenced in the PC gaming v. consoles thread). Game reviews are lackluster (they spend the entire time trying to crack jokes and puns without going in depth or explaining their ratings).
Of course, G4 also shows reruns of The Man Show, which is entertaining. My favorite show is Attack of the Show. It is a hodgepodge geeky bliss. They talk about games, comics, wierd ebay auctions, DVDs, net news, etc. If you don't have it, you wish you did