It's difficult to say what format to go with. I'll try and answer some of your questions.
The PS3 is as good, if not better and less expensive than most Blu-Ray players.
The XBOX add-on is okay but not as good as most stand alone HD-DVD players, but it does have very fast load times. With the prices of HD-DVD players coming down so much, Imo you would be better off getting a stand alone player.
Many of the studios are now releasing in both formats.
A good source for HD-DVD and Blu-Ray reviews and news is here
DVDTOWN I check there quite often.
I have both but prefer HD-DVD.
