I played a lot of games and since I am Sci-Fi fan you could guess I post here too. Let's get started. (only space-like games with Lasers and stuff, otherwise this list would go on forever).
X-Series isnt that great, only the first one is decent.
Freelancer could have been a blast and the story is great, sadly, the game suffers from design choices (rpg-like increase of ship stats) and the battles are boring (Evasion is impossible and the mouse control lets you feel more like a driver than a pilot).
WingCommander Games rocks of course. Especially 3, 4 and 5, these are some of the best games ever made. WC4 still has
THE best space fighter dogfight system. Sadly, doe to their age, these ships lack massive capship battles, story and missions always
flows around these. Well, we got
WC:Saga for that
.
Privateer was way ahead of it's time too.
Nexus is the best space rts made so far. Fact. Outstanding visuals, music, gameplay, story. If they just had made the sequel
(the trailer looked godlike).
The
X-Wing Series (including
Tie-Fighter) is very well executed too, however the story is a little on the short side and I don't even want to mention the difficulty of X-Wing 1. (WC:SO is a cakewalk compared to the original DOS version of X-Wing)
Sword of the Stars sucks. Sorry dude. Continue playing
Master of Orion 1 and 2 or take a look at
Sins of a Solar Empire, that's good.
Independence War 1 and 2 are both pretty good games. However, part 1 suffers from bad mission design almost to the point that it breaks the game. The story saves it.
Homeworld Series: The first true Space RTS using 3d. Still a blast, especially HW2. There are also some neat mods for this one.
Haegemonia: Overlooked in stores, this one is actually a pretty good RTS, crossed with a 4X game. And it's nice. The graphics were way ahead of their time and the explosion effects still impresses in today's Crysis-times. Ignoring some logical errors, you will have a good time leading humanity into the stars in a well written (and easy) campaign.
Multiplayer is great.
StarTrek Games. Difficult to judge. Most suck. Some are good (EliteForce Series, some RTS). Two are outstanding:
ST:Bridge Commander which is exactly what you think and
DS9 The Fallen, an Action Adventure.
Aquanox Series: To me, it's transcendend. Starting with
Archimedean Dynasty, this series provides simply the best game world ever made. Not in outer space but in the oceans of our planet, where a doomed humanity struggles for survival. Mature themes, mature language, not some over-the-top teen game. This is a serious story in a world full of drugs, terrorist, cyberpunks, mercenaries, pirates and fanatics. An outstanding experience.
Tarr Chronicles: Good story, lame dogfights. Far too short. It's getting a sequel now but for what purpose?
Parkan 2 (never even played 1): Always good for a laughter:
Die you ugly monkey!-robots. The rest is trash.
Advent Rising (on PC): The first game of a never finished trilogy,
featuring the best game soundtrack up to this day. It suffers from some glitches and design errors but still tells it's story very well. And it's fun. You feel really powerful when playing this game, imagine JediKnight and MaxPayne in one game.
Halo: Hey, do I need to mention this? Sure, the level design sucks in 1 and 2 but the rest is outstanding.
StarWolves 1 and 2: And RPG in which you control a group of mercenaries. First one is outstanding, second one disappoints. Still, try it out.