Independence War 2 (on gog.com)
The X3 games (not reunion)...on Steam or disc
Black Prophecy...mmo, free to play
IW2 is probably one of the best games out there, but a kind of "stylized" space with a lot of color. Incredible game though.
X3...get a cockpit mod...BIG game, very open, but a variety of ways to play. I like it a lot, but it's still a little intimidating and slow to get going. Kind of like Evochron games.
Black Prophecy...combat, a series of missions but fun.
Straight up combat, it's hard to beat Freespace 2 (gog.com), but games like that get old just moving the cursor around to shoot. You should download Diaspora though, possibly the best space flight combat IMO. And free.
http://simhq.com/forum/ubbthreads.php/topics/3639170/Diaspora_Shattered_Armstice_is.html#Post3639170