There list of distros is small but hey. Thought they would have at least put the top 10 on distro watch in the list

http://www.valvesoftware.com/linuxsurvey.php.
Pete.
Edit here's the Phoronix article. http://www.phoronix.com/scan.php?page=news_item&px=MTIxNTk for some more info.
Update:
Team Fortress 2 is now availible to download. Works well on the alpha 3 release with the beta8 AMD driver.
Looks like egosoft(X univers series) is bringing the rest if the x3 to linux also. there after a linux dev. http://forum.egosoft.com/viewtopic.php?t=329914
Steam seems to gathering some attention by the looks of it.