If I'm t' download games n' take advantage of that 10% back deal, aye. Wouldn't hurt to have a few hundred gigs lyin' around for use neither. T'is worth it, but it's all a pain in the arse. Not t' mention that discs last for long as you take good care of 'em; hard drives can just-plain go if they ain't of the best quality.
I could get AC:III shipped in within two weeks, or I could herpderp around with DOA HDDs (and any fees that come with; namely no shipping refunds) for a month. If not longer.