The New Connection - Digital Cameras, Camcorders, Plasma, LCD, HDTV, Projectors, Computers
This place has the best price on the net right now, $470, + $10 for shipping. I've never done business with them, so i can't vouch for their service
I paid $580 for mine through Amazon.com The transaction went smooth
Right now Amazon has them listed for $502.
I got the 450, I didn't think I needed the extra bells & whistles that come on the 550. If I remember right the only differences between the two, is with the 550 you get Blue tooth wireless, (big whoop) and XM Satellite radio, (if you want to pay the $10 a month for the service). The 550 is about $150 more than the 450.