WOW! This website has so much info it is actually overwhelming. I thought I knew what I was going to do then I stumbled here . . . So what are some of your guru ideas?
The room's slanted ceiling is a real PITA for doing much of anything. I was originally thinking I would do in wall and/or ceiling 7.1 surround. Screen on west wall, projector on east ceiling mount. Built in for receiver, ps3, xbox on south wall.
http://i252.photobucket.com/albums/hh38/07yzfr1/Upsairs.jpg
http://i252.photobucket.com/albums/hh38/07yzfr1/upfloorplan.jpg

huh, no opinions, suggestions or flat out 'Your screwed!'?

Well I might not use the word screwed but... you do have some challenges.

There are several attic builds

CDLehner's
http://www.avsforum.com/avs-vb/showthread.php?t=998182

Mattr762 'Mattflix' build
http://www.avsforum.com/avs-vb/showthread.php?t=1019005

These two come to mind and there are probably others.

Obviously your biggest limit is screen size, but my first screen was 7 feet wide sitting 10-12 feet back and I thought it was great. I think in ceiling surround speakers are a great idea.

Do you have any thoughts on the niche on the north wall? Refreshment area? DVD/blu-ray storage?

In some ways it might work better to have the screen on the east wall, if you don't mind losing the window. You could do a false wall and position speakers easier, because the door won't be getting in the way.

Good Luck!

Edit another build
http://www.avsforum.com/avs-vb/showthread.php?t=756264

Greg

ah ha! Attic build, I didn't think of that search term, thank you. Unfortunately this will not be a "home theater" room, more of a "movie watching" room. This is basically our spare or guest room. We are thinking of a bed on North wall. I don't have a problem losing the window but wifey does . . . Thanks for your input Scopeguy!