I was thinking of blender or 3ds max.
I used to use blender on my 512MB laptop and it works fine - renders take a while but I'd imagine that would be similar for most apps.
I got a lot of lag when animating but taking off the sub-surf modifiers got it close to real-time. wack 'em back on for export & bob's your uncle.
never used 3ds so cant compare, but blender does the job fine for me.