I received an email today stating that I was approved for the rebate. I sent both the "receipt" that is available for printing on Buy.com's website as well as the original packing slip (along with the other required enclosures).
I was a bit surprised as it has been my experience that most companies will try at least once to deny your rebate request, especially when you purchased the product from an online merchant. The usual reason for the denial is failure to include the original store receipt. In each of these cases, I've simply resubmitted the same information, along with a pissy letter and I have invariably received the rebates. I swear I think these rebate companies purposefully deny some percentage of rebates as a matter of course in an attempt to lower the cash outlay. This is in keeping with the whole purpose of the rebate, which is to offer cash back, knowing that a large percentage of the general public will be too lazy to pursue, and/or fight for, their money back.