Planetary Annihilation: TITANS

If you want an RTS that isn't going to bore you in ten hours or less, go look up Supreme Commander.You might not get orbital mechanics or 'death stars' (which are way too expensive for practical use to begin with), but what you do get is a much more detailed, refined, replayable and less horribly performing experience than what's offered here.

Community mods such as Legion (although I swear Legion used to be slightly over-powered back in the day, but I haven't tried them in a while) expand the game further and the recent introduction of Co-Op galactic war give the game that little bit extra I always thought it was missing.

They are powerful and definitely worth persuing as they function as an advanced fabricator unit but also have strong combat ability.

The Queller Ai mod adds that difficulty to the game I thought was always missing along with greater strategies from the Ai that make it must have mod, along with the galactic overhaul mod.

Really complex and complicated strategy game with a unique art style and setting!