Some random thoughts:
You need to think about the ambient light levels in your room, this
will dictate how bright you really need the projector to be. If you
can make the room totally dark, you can get by with a pretty dim
projector, say 800-1000 lumens. Screen size plays a role here too,
though, the larger the image, the more lumens you need to get the same
screen brightness.
For games, 800 x 600 doesn't really look that good, 1024 x 768 is
acceptable, but barely. I have to turn up the FSAA to make it look
smooth. Once you start racing, you don't notice it as much. The size
really creates an immersive experience for me. I would love to see
1600 x 1200 or even something like 1920 x 1080 for a picture this
size. Maybe in a few more years.
Many projectors will sync to these higher resolutions, but you want
one with as high a native resolution as you can afford.
Bulbs aren't really that expensive per hour. You need to take the
information you get from projector central (hours of bulb life), then
find out how much replacement bulbs for that projector cost, then do
the math. Most bulbs these days last well over 1000 hours.
Check out http://www.racesimcentral.net/
can digest in a lifetime. Particularly the digital display, HTPC and
*** forums.
Another good company is NEC. Good projectors, awesome warranty.
A projector with optical zoom gives you a lot of flexibility in
projector placement.
If your cable length is much over 6 feet, invest in some decent VGA
cabling to avoid ghosting, rings, etc. This doesn't have to be
expensive, if you shop around. Figure $40 for a really good 25' VGA
cable. Belkin (even their high end cables) really doesn't cut it.
Good luck,
Gerald