Talking about screen size, I think the size of your gaming space is important. I put mine in my room so a 24" LCD is really big enough even on a 4 player split game. If your setup is on your living room I think 40" onwards is more suitable =)

Screen size is directly related to the space or room your set up is going to be. No point getting a 42" screen for a 7' x 14' room like mine. Bigger screen size is irrelevant in a small space. Screen size to space size ratio is important here. If your hall or room is huge, please by all means, get the biggest screen you can afford and show off here =)