I purchased mine at Bestbuy just so I could get the geek squad protection plan. I hope i never have to use it but if I do its a quick visit to any best buy and its replaced.
I bought mine at Walmart and my son bought his at Bestbuy. His 2 year coverage cost more than Walmart's 3 year coverage.
I haven't had a single thing break on mine so I haven't needed it, but it gives me peace of mind. My son may need to warranty his with motorola for a cracked back though. Not sure how that effects the warranty that he purchased since I think it is tied to his particular serial number?