Vangar, have you ever looked at EVE? If you like Sci-Fi then you will probably really like EVE. It's a huge space trading MMORPG which is quite hardcore. I played ti for a while when it was first released and it was great, but quite complex. I have been tempted to play it again for some time.

I also used to play the online game Earth and Beyond until EA stut down the server!!! That was a very nice space trading style game.