Who doesn't love killing zombies? Maybe it's due to the fact that the walking dead used to be peoples friends and neighbors, but there's no denying that zombies make great videogame villains. Apparently Valve Software feels the same way, as its next game is shaping up to be one of the finest zombie titles in quite some time. GameSpy done numerous previews of Left 4 Dead over the last few months, but they only ever saw the PC version of the game. That is, until now. GameSpy had a chance to spend some time with the Xbox 360 game at Valve's offices in Kirkland yesterday, days before it was to be shown at this weekend's Penny Arcade Expo.