f world domination isn't good enough for you, perhaps you should consider something on an even grander scale. Masters of Orion 3 gives you the world and more to conquer and bend to your will. There's lots of room for diplomacy, but you don't found an empire by being nice to aliens all the time.
At your home planet you decide how to spend your resources, invest in military and agricultural research, train spies and wage war. There are layer on layer of endlessly complex options for every aspect of life in your colony. There are spaceships to build, planets to explore, aliens to meet, and governments to join or crush.
The Orion series has been around for a long time; the original, Star Lords, was a DOS game. Consequently it has some very old fans, and they are passionate about the game and the 4X (explore, expand, exploit and exterminate) genre.
There's plenty of activity on the chat boards at www.moo3.com, where everyone seems to have an opinion on how the game should be designed and played. There's plenty of support and tips for newcomers, and I would advice inexperienced players to go there for help. Otherwise there's a massive 150-page manual to refer to.
You're bound to experience the JOMT syndrome, as they call it on the message board. That's the “just one more turn” illness that'll keep you up until the wee small hours. Playing Masters of Orion 3 is one of the complicated things you can do. It involves keeping an eye on so many different aspects of the game at the same time that you need more than one brain to play it. But once you've gone through the first few round, you'll be hooked.
I hesitate to unleash such a time-hog, but if you really want to rule the universe it's probably best you don't leave the house.