The game is fairly stable for me (running 1600x1200 with maxed graphics on Win 7 x64) - I haven't had any crashes beyond the know Alt-tab problem and when trying to load a corrupted save done after some other bug hit me. So I don't have any specific suggestions, but I can give some tips on how to debug the problem:
A good place to start might be to disable and/or set to minimum everything that you can. After doing that, does the game still crash? If so, maybe it might be a corrupt installation or not having enough ram. (Does your computer meet the system requirements?)
If the game works OK with everything disabled, then you can try gradually enabling or increasing one or two features at a time and re-testing the game. If it starts crashing after you've enabled or increased some setting, back off on it, write down which setting it was, make sure the game works again, and then try enabling some other feature. Keep testing things, because it's possible more than one feature may be causing your problem. In this way, you'll get a picture of which options cause the problem, which then hopefully will give a clue about what the cause is.
