I would have to say serious sam, just because last lan party I went to my old computer could not handle it and that was the game they wanted to play. Now that I have my new computer built and up and running what a difference.

But I ran into a problem with installing Serious Sam in my win2k. I could not use the auto setup that pops up when inserting the disk. I had to browse for the setup file on the disk and run it.