The Strategy genre of games are based on the use of strategies and tactics. The player is usually given some type of force and must make decisions on how to complete and objective without losing their forces/resources. The strategy genre also encompasses RTS, RTT (Real Time Tactics) and Turn-based Strategy.
Some good examples of strategy games are,
-Total War series
-StarCraft I & II
-Warhammer 40k Dawn of War series
-Command & Conquer series
-Red Alert series
-Dai Senryaku series
-Homeworld series
And I guess you could probably consider Anno and Civilization strategy games.
I personally like Red Alert, Civilization, Dai Senryaku VII, and Warhammer, and even though I've never played it, Homeworld.
So forum, discuss strategy games and such.