The Dark Age of Camelot DR needs to be completed at some point

A top-down third-person shooter. You are stationed on one of Jupiter's moons which was recently colonized, and are called in to investigate the cause of a power outage. Aliens threaten to overwhelm a nearby colony. Only you stand in their way.

Guild Wars is an online game with some resemblance to Roleplaying games. It's quite popular, no doubt due to having to pay no monthly fees. The game offers an MMO experience in the different town, where the "countryside" and missions are "instanced."

Giants: Citizen Kabuto is a third person shooter from Planet Moon and Interplay. Gameplay is unusually varied, and spans three campaigns with three characters - the heavily armed, high-tech meccaryn Baz and his squadmates, the sword-wielding, spellcasting sea reaper Delphi, and the enormous, village-trampling Kabuto himself.

Rise of Nations: Rise of Legends is a real-time strategy game for the PC made by Big Huge Games, and published by Microsoft. It is a spin off of the popular game Rise of Nations, released in May 2003. However, rather than being a historical game, it is based in a fantasy world, where technology and magic coexist. It was released on May 9, 2006 in North America and on various dates around May 26, 2006 in the rest of the world.

Serious Sam: The Second Encounter is an FPS from Croteam and Gathering of Developers. You play as Sam "Serious" Stone, and do battle with thousands of alien nasties throughout various historical set-pieces, using an array of diverse and enormous weapons.

Close Combat: First to Fight is a squad-based military first-person shooter. The player commands a fireteam of 3 other U.S. Marines in a realistic, though fictional scenario where the United Nations sends Marines into Lebanon when their Prime Minister falls ill and Syria and Iran send forces to bolster certain factions.

Civilization III is a turn based strategy game from Firaxis Games and Infogrames. The basis of Civ 3, like in the previous two, is building a civilization from a primitive tribe to a modern empire, developing cities, technology, and culture, and conquering weaker empires while making peace with stronger ones.

Full Spectrum Warrior: Ten Hammers is the sequel to the Full Spectrum Warrior.

Command & Conquer: Red Alert 2 is an RTS from Westwood Studios and EA. In the alternate universe where Germany never rose to power, the Allies and Soviets are at it again, but this time the Soviets have launched a full scale invasion of the US. You can command Allied forces and repel the invasion, or command Soviet forces and lay waste to the US and its allies.