Yet another follow up to my own post...
I spoke with a guy that was fairly knowledgable in Yamaha's lines. the 557 line will also get an upgrade to the component up... instead of just S-video up conversion, it will have composite. the 457 will have S-video up (prior, it had none). In addition to the XM satalite support.
So now the big question is do I wait a month or so for the 557 model, or go with the 550... How nice would composite component up be?
-Mike