If we only count people that play over 5 hours a week:
Xbox: even D/R more libertarians than general population(about 2-3x)
PS3: Lean D
PC: Democratic, a lot of anti-capitalists.
Here's the leading ideology of the games based on forums I visit
Wc3: social democrats, half of posters from EU half from US
Sc2: US "liberals"
Dota: no coherent ideology, just drunken rants.