May I also suggest,
http://www.terminal26.com. Check out the 'Shop' -
http://www.terminal26.de/shop/shop1p.php?lg=eng section. Thay have many models, and again, can be converted to .x easily for use with fpsc.
They also have many models to choose from. These 2 sites have been favorites of
'3D Game Studio' which I own the Pro Version, but the scripting took a C++ developer to make good use of. For me, too much time and 'cough' effort.
But again, I have successfully converted the models without a problem! I own the complete set of Terminal 26 models and have converted them without a problem. If you purchase and Terminal26 models and have conversions issues, let me know, I'll try to help.
Not sure about their terrian pack and sky cube pack. I have not tried to use them yet.