This adding up prices really gets tired, my brother just got a 360 at toys r us for 399 and got a free $100 gift card, and used it to buy the HD-DVD add-on. So he got the 20gb + HD-DVD for a total of $499, and there are deals all the time with the 360 that include games and such. I think Circuit city or Target is running an ad right now that includes a free wireless control.
Another price you must add to the PS3 is HDMI or Component cables to view your PS3 in Hi Definition. The PS3 only comes with Composite so in order to view it at 480p/720p/1080i/1080p you need to fork over an extra $60-$120, a lesson I had to learn the hard way.