Something else to consider is the software you will use for playing blurays.
Youve got a few options and all have their own problems:
Cyberlink Powerdvd 9 -
Pros:
Upscaling is the best you can get
Easy to use software (when it works)
Bit community so problems get found out quickly (though that does not mean they get solved)
Cons:
Expensive/HDMI lpcm was broken until a recent patch and can be flaky still/bloated/doesnt play hddvd/downscales HD audio to 16/48
Windvd 9 -
Pros:
Plays hddvd
Cons:
Expensive/LPCM over HDMI is still broken/audio setup is confusing and irritating/support is nonexistant/downscales HD audio to 16/48
Total Media theatre 2/3
Pros:
LPCM HDMI actually works
Upscaling is good
Good community and problems do actually get fixed and taken notice of
Cons:
Just wont work on some people's pcs
downscales HD audio to 16/48 (except using re clock on build .125 which is unstable)
cost
Slyplayer
Pros:
Free

Wont downscale audio
Might bitstream without asus xonar

Excellent support (same company that makes Anydvd)
AIming to be slimline and simple
Cons:
Doesnt exist yet
Aiming high with its intentions but might not actually work
Really quick summary there, basically all of the softwares have their own issues and problems, and this is by no means a comprehensive list. Best thing is to try one/all of them (i think they all have trials) and see what works for you.