Three things that I can offer you here.
1) Mount the projector to a ceiling. The reasoning is three fold here. First, the projector can't have beer spilled on it if it isn't withing reach of falling beer. Second, the position is stationary so once the focal length and distortion can be correctly compensated for. Finally, the heat output is more easily vented in one direction if it's on the ceiling.
2) Do not plug and unplug from the projector, run one wire to the projector and connect/disconnect from the other end. Two points to this suggestion. First, the projector heats up, and the connections generally weaken over time. Connecting to/from the projector will more quickly wear out the connection. Getting a replacement connection board is generally as expensive as a new projector. Finishing up, the less touching of the projector the less focus adjustments need to be done. This is good for increasing the lifetime of the projector, and making that bulb last as long as possible.
3) Don't spring for a screen. Retractable screens cost as much as the projectors, and they are easily damaged. The easiest and cheapest method for creating a screen is with a sheet of MDF, two quarts of primer, fine sand paper, a roller, and a gallon of white paint (flat finish).
Designate one side of the MDF as the screen. Take the fine sandpaper, and apply it until you can slide your hand across the board without feeling any fibers (this is about an hour worth of work, but remember that you are surfacing and not restructuring the wood, BE GENTLE!). Blast the piece with air, then coat the entire piece with primer. This primer seals the board, and will prevent moisture (beer?) warping. Wait until dry, then apply the white paint in an even coating with the roller. The screen may still be shadowed by the primer at this point, do not worry about it. Wait until the piece is completely dry, then sand any imperfections lightly. Once the sanding is done, blast it off again and apply another coat of paint. This coat should make the piece pure white, but if it doesn't a third layer won't hurt.
Once the screen is fully dried, you can hang it easily with four screws. The multiple layers of paint prevent moisture damage, and create a surface that is surprisingly easy to clean should anything stupid happen. You are giving up a wall for the screen, but should you need to move out the screw holes are easy to patch. If you want to get an idea of what flat white looks like, tilt your head back 90 degrees. Flat white is used for ceilings.
Advice session over, I would just purchase a TV instead of a projector. The potential pitfalls associated with a projector are numerous, and you've got to do a lot to get the image quality somewhere worth watching. Unless you've got a huge man-cave style common area, the largest picture you're going to get is likely in the 60-70" range (and at 1080p that'll look like crap unless you're a couple of feet back. A 50" television will use less power, have a longer lifetime, be well within you budget, and cause 800% less head aches. If everyone is hell bent on a projector then I'd suggest you get a lamp, 100 watt bulb, and a dark shade. If you have a place to plug the lamp in (and an extra socket for the devices), once you turn off the lights the shade projects a perfect circle on the wall you are pointing at, and the light is even across your screen (the screen is about $70 in components, so it's easiest to create it and experiment before getting a projector) then a projector might work for you. That's a whole lot of ifs, and only one way that everything comes together in a reasonable manner.
Edit:
50" 1080p Television
Clear acryllic sheet
HDMI selector
Go about this like a bar. Mount the TV to the wall, surround it with 2x4 beams, spacing them so the TV can be slipped into the setup should it need to be replaced. Cover the outside with acryllic, screwed into the 2x4 beams. Light still passes through, so the remote will work. Vomit/beer+acryllic+gravity=mess on the floor. HDMI selector gives outside access for DVD/Blu-ray/gaming consoles/computers. If the selector is beer splashed, then it's a cheap replacement.
