Space Federation - Star Reach

Star Reach was released in 1994 for MS-DOS. It was one of the first games I've ever played (I was around 10 at the time). As one of the first ever space-based RTS games, Star Reach boasts numerous features, including very acceptable graphics for that era, ability to micromanage your fleets, planet economies, and base structures. Star Reach also features a very neat multiplayer mode - Two players can play next to each other, one on each side of the keyboard. The screen is then split down the middle.

You and your friend can enjoy the galactic battles together, either on the same side, or as enemies. (OK sure you can always peek across the monitor at his base, but come on, this was the 90s, and I'm not sure the concept of Internet gaming caught on yet).
The plot takes the player to the 23rd century, where humans have made contact with several other alien races (some including gaseous entities, squid like aliens, grasshopper monsters, and of course, robots). Representatives of every race attend a peace conference held on a planet, but unfortunately, terrorists destroy the planet and all the leaders perish. As a result, a galactic war breaks out among all the races, and the player can choose their side.
Admittedly, all the sides DO have the same units, so don't be surprised, and I don't remember there being a single player campaign or anything. Star Reach is meant for skirmish mode, where players pick sides and battle another player or other AI (up to 3 other computer players).
Some other drawbacks of Star Reach - eventually, the game does get tiring, as the AI is not as aggressive as you'd like it to be. I've re-downloaded the game and ran it on windows XP out of nostalgia, and perhaps I didn't realize it as a kid, or it just worked better on DOS, but there seems to be some sort of limit to the total number of ships/objects the game can support (yours and the enemy's).
While it is unlikely that Star Reach will ever be considered in today's market, for the classic PC game enthusiast, Star Reach will prove to be an intriguing game. Certainly not comparable to Command and Conquer or Warcraft, but the classic RTS element is there, and it's worth trying if you have an afternoon or two to kill.