Warcraft is real-time strategy game released by Blizzard Entertainment. Warcraft III's single-player campaign is laid out, similar to that of StarCraft, being told through all four of the game's races in a progressive manner. Multiplayer mode allows for play against other people via the internet, instead of playing against computer-controlled characters as is done in the single-player custom game mode. This is a great game that works well on a netbook for all you RTS fans.
Halo Combat Evolved
Certainly one of the most fun shooters of all time, Halo continues to be an amazing first person shooter set in the alien world. You play the role of the MasterChief, who is an elite soldier fighting the Covenant, an alliance of an alien species. The brilliance of this game is the gameplay which include hectic foot battles, plus you get to drive plenty of different vehicles that range from a military warthog to alien hovercrafts.
This is yet another popular RPG game that works well on a netbook. Produced by BioWare, it is based on the third edition of Dungeons and Dragons and Forgotten Realms. The game is based on the concept of building an internet-like model for a massively multiplayer game, allowing the end users to host the server. Check it out if you're a fan of such games.