I've been pressing my luck for far too long by not having a backup hard drive on my system. So I need to just do something. I don't need a huge HD, 250-500GB would suffice. I've read tons of reviews on Newegg and Amazon, and I can't decide what approach is best. Should I buy an enclosed drive, or a drive and an enclosure. Being my main concern is longevity/reliability, is one approach better than the other? It seems like all the popular drives I've read about (Seagate FreeAgent, WD MyBook, etc) have some non-zero infant mortality rate. Is there a line of consumer drives that are known to be more robust than others? Any advice appreciated.