Both Freelancer and X3 are fun games, however, it should be noted that X3 is FAR deeper then Freelancer. In fact, while Freelancer is more of a space shooter with some basic trade elements thrown in, X3 is almost an economic simulator with star ships.
In X3 there is a dynamic market, and the player can own, control, and build hundreds of ships and factories of all different types. From trade ships to heavily armed capital ships. And going back to the dynamic market, you as the player can find holes (AKA opportunities) in the market and then fill them, either by trading or if you have more money, just building a factory there to fill the need. Its quite possible to build an entire trading empire in the game, in fact. Or a military empire, for that matter.
However, due to this complexity X3 has a somewhat steep learning curve, and as others have said the voice acting and character models are generally atrocious.
Still, if you are interested in a deep and complex space combat/trading/empire building X3 might be the way to go. If not, then Freelancer has an interesting plot and pretty good voice acting, its just too bad that you can only control one ship in it.
Anyway, if you've got any more, keep 'em coming. I'm liking what I'm hearing so far. Especially intrigued by Freelancer.