Damn, tough call... I think you're best bet if being frugal is a decent laptop and go external display to a LCD of your choosing. Most new lappies have HDMI outs on them. I'd stay PC based for flexibility. Speakers are whatever works really, there are a ton of 5.1 systems out there...
Edit: I would not touch a projector, they are great in low light environments - not so much if day light is around...
1971 23' Oday Pop Top
You can't steer a boat that isn't moving? Just like a life - P. Lutus