I just got my PT-AX100U (720P) projector and Pioneer Elite VSX-82TXS receiver which I plan to hook up my gaming PC to via DVI>HDMI adapter. Would I be better off outputing games at 1080p and having the receiver or projector scale it, or outputting at 720p and setting the max AA and AF that I can?

I can't see how it would help to have the computer output at any resolution greater than the native resolution of the projector. I have 900u and run bf2 at 1024x768 because it does not have widescreen support. It appears a bit streched but looks pretty good overall.

Any other game and I run 1280x720.