The X series of games are the only ones I know where you can be a lawman, trader,mercenary, or empire builder or all of them at once. You can grow a trading empire or own dozens of ships and make raids right into enemy territories for fun and loot. Asking for info about making a empire of any kind is ok, I'm sure, but trying to see what you really want to "be" in the universe is the most important thing.
New games in the future will be even more about having a place to 'call home' when your tired of everyday life and want to sneak away somewhere for a while, having games you can truly feel like you belong in will be better than third person games where they think you all need to feel like god..lol. I look forward to another generation of games even more detailed and immersible than these, but it'll take some work to make it so.
