Update: As ever, our intrepid SlashGear commentors come to the rescue. It looks like Amazon incorrectly tagged several iPod models, causing them to be left off the hard-drive based sales list. As of update, they've still not corrected the issue; however in the full portable audio chart the iPod Touch pre-order is sitting happily at the top (complete with prescient user reviews).
Cynical we techies may be about Microsoft's Zune and its appeal as a PMP, but the general public once again demonstrates that at the end of the day price plays one of the biggest factors. Since the cost of the white 1st-gen 30GB player dropped to a mere $169.99 on Amazon US - thirty bucks more than the $50 reduction Microsoft announced - it's hit the number one spot on the retailer's hard-drive based PMP sales list.