Lately my gaming has been almost exclusively on PC. Basically...better graphics (my computer is pretty beefy, I do a lot of rendering), more customizability, no shitty xbox interface flooded by ads (along with shitty Mii ripoffs), much better prices (steam), having everything in one package with no discs (again steam). Add to that a wired xbox controller, emulators, mods, tons of free games (League of Legends, Team Fortress 2, etc), keyboard/webcam chat and webplayer games, among other things.
For example, I can play Just Cause 2 fully maxed out on everything on PC with better graphics, frame rates, etc. than the console versions, xbox controller and everything. Alt-tab and I can switch to Majora's Mask or Banjo Kazooie instantly, with the added convenience of save states.
Basically it's not that the graphics are better so much that the graphics are better, along with all the other good stuff you get.
Up until now I've mainly been a console gamer but the current console generation is just so far behind that it's really hard to pass up that kind of convenience. Consoles do have their advantages of course and come next console generation I'll probably do a lot more console gaming but who knows.