no you don't "need" one per say. But if you want to get the full use out of the system then yes you should get one. its made for hi-def gaming. but i knew a few people who don't have one and still have a 360. the graphics are definitely an upgrade but not in hi-def like they should be. IMO, the difference is like night and day. you'll see where that extra went when you game in hi-def</p>