Black Sun Empire
Well, the game is rather complicated. First three or four of my games vs AI were a complete failure, I joined my first MP game only after 2 victories on multiple impossible AIs, and still I had a lot to learn. Now I consider myself sort of experienced player, I have 1 MP victory, but half of the players in this game are better then I am.
So... see for yourself, but if you're totaly unfamiliar with game playing against people could be a total dissapointment. I recomend playing vs AI first, I can guarantee that would be fun (I just remembered my excientment first time I tried crossbreeding

). Then, when you are able to defeat AIs blindfolded and hads tied - it is a good time to join MP game.