I've noticed that every display type I can think of has been discussed somewhat here, except projectors. Any opinions on those? They seem to me like a good option, especially for PCs: big screen for relatively cheap, regular aspect ratio, decent resolutions, doesn't take up much room; so what would be the catch?
There's a couple catches. First, you need to have enough space. It pains me greatly that I own a projector and can't use it due to lack of space. The projector itself doesn't take much space, but if you want to get any decent projection up, you need to have a fair amount of space. Around 7-9' of throw space is not unusual. I personally don't have any such distance in my house without making things very very awkward (I don't want to have the projector sitting in the kitchen).
Second, the price is much higher than most monitors. And generally you get worse resolution. Projectors generally start at about $1k and up, and higher resolutions cost more. You can find used ones, but don't do what I once did and buy a used projector made by a company no longer in business. I'll explain in my next point.
Third, they have a horrible life rating. Almost all projectors you see on the market are either LCD or DLP projectors, which use a lamp by from which they produce their image. Read up on the specs and look at the part that says "Lamp Life" or "Bulb Life" Most simply don't last that long. The 1,500 hours quoted earlier on this page is typical. And if you look at the cost of bulb replacement (hint: not cheap), you can see that you're going to be spending some money. And if you did what I did and get a used projector from a dead company, you'll find that the bulb costs were almost astronomical.
Fourth, for most projectors, you have to eliminate almost all light sources to really see anything. That can make things a PITA to use, where everytime you turn it on, you have to draw the shades and close the doors.
If you can deal with all the above, then by all means go for it. I've played four player Halo on my projector at a friend's house, and it was really sweet. The screen never felt cramped.