Well, my laptop has a 1080p HDMI output that I use to my new office 26" Toshiba 720p LCD HDTV and it's very, very good. The TV has very little problem scaling the 1080p down to its native mode. Can't say I know anything about projectors though (but I don't see why it would be any different).
Firing up a PJ everytime you want to use your computer seems a bit unusual.
brucek