Personally, I don't think the last four belong on the poll. Games such as the Unreal Tournament series, Half-Life/Half-Life 2, Doom series, Far Cry, F.E.A.R., Quake series, and possibly the Call of Duty series should be on there instead. Most of these games revolutionized the FPS market, while I would be willing to bet more than 85% of PC gamers never played any of the Tribes games or Red Faction (which wasn't all that great in comparison to other shooters at the time anyway). Besides, Tribes, Red Faction and Halo were all on consoles as well.