seagate hd's come with a 5 year warranty...they cost a bit more, i have never had any troubles with them. if you live in the US check www.newegg.com they usually have great prices, or you can go to bestbuy and get one with a bunch of mail in rebates.
GO WITH MAXTOR DEFINITELY!!!!!! maxtors the best for ur xbox since its the most compatible. its the easiest to unlock and lock. some drives cant be locked and u dont want that. if it cant be locked say bye to xbox live. western digital is another good 1 but some cant be locked. seagate is also good and its much cheaper but cheaper means it isnt as good . mdsup is right go to newegg they r kickass. frys electronics has the best rebates but the best deals are mail in rebate.
