trackmania is my number 1. havn't played trackmania 2 yet. but they say it's atleast just as great. if i have to believe x-fire then i played trackmania over 3000 hours. xD only to get beaten by unreal tournament whit over 6500 hours.
1. Minecraft (AnjoCaido Launcher)
2. World of Tanks
3. RuneScape
4. Kerbal Space Program (There is a free demo of the game under the "Downloads" tab of their website)
5. Battlestar Galactica