Wing Commander Saga....
[*]Its free
[*]It's 10GB extracted size
[*]You can turn up the detail way high (mine does this on absolute maximum FSAA and Anisotropic)
[*]These screenshots suffered a lot from resizing... originals are at 1920x1080
Get it: http://www.wcsaga.com/
Hellcat Fighter, these can do atmospheric flight but aren't that good actually
Arrow Fighter. Loads of fun in a small package... not much cannon firepower on these though
Yet another escort job ready to turn into a major battle
Making absurd attack runs on big ships... his buddy just got shot to pieces
Hunting pancakes... thats what the game is about mostly
Big ships... with loads of gun turrets