well speakers are fine for lan parties too. (unless they are really big ones of course) Though headphones would be better, I won't bother buying one since I only organize lan parties like 2 or 3 times per year.
A surround sound setup of speakers is way better than headphones any day. Headphones are only 2 channel, not true surround sound. With good surround sound speakers you can perfectly hear the location of footsteps, bullets, etc.