Now lets not make it sound like projectors are total crap. When set up properly, calibrated and displayed in a very dark room, they look stunning. My Infocus 4805, while just 480p, gives as good a picture as my parents LCD. The extra you get with a projector is a move-like atmosphere (if you find that to be a plus) and a HUGE picture, which should not get discredited. 1080p resolution at 82" isn't unusual. At a normal viewing distance, it'll look awesome.
ykyagami, don't buy into the argument that an 82" picture will look blocky. It won't, as long as you're not five feet in front of a 6.8 foot screen. When you sit at a normal viewing distance, you will not notice any pixels. I notice some pixels on my 64" screen, but only when I'm less than 1.5x (the screen width) away and I only have 480p resolution.
Also remember that image quality doesn't just come down to resolution. Contrast and color reproduction are also important. LCD's definitely fall short in the contrast department.
That said, yeah, a decent 1080p projector isn't real cheap, but neither is a 30" LCD monitor. Also, with a projector, you must consider placement of the unit as well as possibly a screen, unless you just want to paint the wall. Bulbs are commonly hundreds of dollars, but should last for a long time (IE: over a thousand hours, typically, sometimes more, sometimes less).
I guess my point is you need to determine how important screen size is. While the resolution on my (smallish) 64" projector screen wasn't as good as my brother's 17" LCD, always came over to play his computer games on the screen with my home theater surround setup. The audio, as well as HUGE gaming picture made the gaming that much more enjoyable.
Determine how important screen size is for you. If it's worth any extra money and a little more elbow grease in setup, go for it. If you have the room (remember your sitting distance from the screen should be 2-2.5 times the screen width) for a large screen and decent viewing distance, cool.
Play a game like Battlefield 2 and look at your teammates as they walk by you, literally three feet+ in height on your screen. Tell me your LCD is as immersive.