I gotta say, I don't understand why Seagate is discounting their drives so heavily when they're already the only game in town when it comes to a 5-year warranty. Maxtor seems to have given up on rebates and is just going for a lower OTD price, Western Digital still does rebates, but it seems to be two at a time on a single product rather than just one (and they're priced higher than everyone else), and Hitachi is just in their own world.
They're either trying to achieve a certain market share by a certain date, or they're in financial trouble. Either way, they will BE in financial trouble because there's no way you can keep selling product like this at 20-30 cents per gigabyte and turn a profit.