I can hit them with da schnapper!
My favorite game is and will always be Command and Conquer Tiberian Sun, simply because it was my childhood. I didnt played the popular games everyone played at school. Instead i went home and played this game. It got me into RTS games and modding them. Even now im still playing and modding it.
The graphics may be old, the gameplay is just lovely, the game is pretty balanced (even if it doesnt look like it is) and requires a lot of anticipation (as with most RTS games).
I bought it since it came out, then i 'rebought' it by buying The First Decade and now its released as free. One of the best RTS games IMO