be sure to check out the freespace 2 open source version as well (requires a copy of the original to play though). After FS2 the genre basically died and the studio went backrupt so they released the source code for free.
The fan community ended up updating the game engine with modern graphics and their own custom campaigns.>>2846
Both are space games but freespace is much more story/capmaign oriented. It had a very extensive single player campaign as well as multi player (one of the first modern games in that it had voice chat and a map/scenario editor that came with the game).
I never played freelancer but I think its like another 'Elite' clone?, you can wander around the galaxy like han solo?
Freespace OTOH is definitively in the 'military science fiction' genre
the soundtrack is part ambient part electronic in the style of 80s/90s scifi-techno.
The music, the combat system, the storyline all really add to the atmosphere.
You can get the original game and the sequel for $10 on GOG, sometimes they go on sale for $5