Freelancer is a space-based combat simulator/Extremely open-ended Role playing game. Spanning several star systems, and easily 100 hours of gameplay, the game was a marvel of its time. It has an excellent plotline, set in the same universe as Starlancer, and it will keep you engaged for quite awhile.

You play as a freelancer, or mercenary, out to make his way in the universe, and you eventually become entangled in a plot of galactic importance.

The controls are awkward at first, being one of the few mouse based games rather than WASD for control, but it quickly becomes intuitive.

One of the first non-MMORPG games to sport an online mode that could handle up to (in one case) 100 players in a persistant universe, the game is almost considered to be an MMORPG. It really is the NWN of Space RPG's.