A terabyte is good. Two terabyte drives are becoming fairly common. In truth most folks won't fill up one unless you are a serious music or video fan (or you feel the need to get every gaming pdf ever published like me). File sharing sites, especially ones where teens go for music are actually the most risky. But a lot of mainstream sights get hacked and loaded up with Malware. There have been problems with sites like ESPN and the New York Times.