Want a (complex) single player space sim, but can't wait for the big Kickstarted ones to come around?
-Then forget that scandalous, insulting heap of console-reject dung, X Rebirth. Pretend it doesn't exist, please, and get X3 Albion Prelude. Then look up and install the X Rebalance Mod, colloquially known as XRM.
This text is actually a recommendation of XRM, as it makes Albion Prelude (and Terran Conflict) an almost absurdly better game compared to the release version, and I for one will never play TC or AP un-XRMed again.
It's very important to note that X3 is a peculiar game for a peculiarly patient type of player; if you just want to pilot a fighter through a neatly structured campaign of epic missions, like Tie Fighter or Starlancer, X3 does not really deliver, unfortunately.
What X3 *does* is provide a massive sandbox full of awesome but complex toys and pretty much leaving the rest up to you, giving very little help or guidance. If you're new to it, expect to be frustrated, irritated, outraged and annoyed, in heaps, but if you're up to the struggle of getting to proper grips with it, X3 is very, very rewarding of your patience, and so far the closest you will get to a properly realised single player space-economy-sim sandbox.
-Again, don't forget to install XRM! It's still very much the same game, but so much more and better.
As a service notice, Albion Prelude is Terran Conflict with different "plots" (campaigns), slightly updated graphics, some added scripts, and a couple of new ships. They are essentially the same game, and the only reason to play TC over AP is if you prefer the plots of TC. I personally especially miss Operation Final Fury in Albion Prelude.