X3 Reunion and SoftTH
X3 Reunion is an incredible space flight game. Very openended, tons of options and play styles, all around one of the best space flight games I've played. It also works nicely with SoftTH if you have a decent video card.
Framerates with a GeForce 7900GS primary and a Geforce 7300 Secondary were decent. Best results were achieved with the resolution set to 3072x768. 3840x1024 worked ok, but was a bit more jerky
Setup Instructions
Setting up SoftTH with X3 is quite simple. I used the Steam version of X3, so if you have the CD version, I'd advise dropping the files into the root directory of the game.
All you need to do is copy the d3d8.dll, d3d9.dll, and softh.cfg files to the steam\steamapps\common\x3 - reunion directory. Then, get into steam, and load up x3. It will show you the launcher for x3, just select "graphics options" and pick the resolution you want from the drop down. Then load up the game, and it should all work correctly.
The only oddity I noticed is that pressing printscreen to take a screenshot freezes the joystick, just move the arrow keys to regain use the joystick. Also, due to an amusing code usage by the developers, the main menu system looks odd.
Screenshots
Here are some screenshots from x3 Reunion using SoftTH
