new user here.
Though I'm not a gamer I'd like to tell you all about a game called Nexuiz www.alientrap.org/nexuiz/index.php?module=downloads It's played online and it's a lot like UT2004. It's got OK graphics and runs smoothly with USB 2.0(dont know about firewire though)
It's absolutely free and only takes up approx 200mb, unzip to a folder of your choice and play.
I use PStart to get it going because I don't know how to otherwise but if someone finds out please do tell