amblix, is the $10K the real budget? If so, it will go very fast with the list of components.
If you are using a HTPC for video rendering, you don't need a scaler.
Don't forget about a screen for the projector.
Wiring too.
5.1, or 7.1 system? Light controlled room or not controlled?
Recessed speakers including sub? What is the construction of the room - 2x4 / 2x6 / no stud basement? Size of room (including ceiling)?