why not get Blender3d? Its free and you have a modeler,animator and world-editor!
Gamespace etc
BTW,You can look yourself,try the demos and decide what fits best to you.
Look at this thread : http://www.coniserver.net/ubbthreads/showflat.php/Cat/0/Number/469119/an/0/page/0#469119
its a list of the most used programs at time
BTW,Instead of buying some models that you would have to reskin and deform(if some needed) i would get poser,were you can change a model to fits your needs and later with some polygon reducer get some polygons out
hope i could help.
Dark
Just a fan of art!