lcd's consume much less energy.. if you're making an attempt to be "green".
plasma's may have much better contrast..
dlp's usually the cheaper option, but pretty much take up more space.
if you have a fireplace, and having to deal with it with locating furniture and tv to get the best viewing position..... really consider the LCD/plasma options.
I"ve had a 52" wide screen projection for a few years. and wish had the lcd over the fireplace because of seating... fwiw...