Max is the modeling juggernaut with it's plethora of tools. The extra free scripts also help. Maya, from what I gathered, is the best lower-tier solution for animation (the honor goes to MotionBuilder), so if you're an artist who wants a package for animation, it seems like Maya is like it.
I know its not one of your two options, but if you really want to use a nice modeling tool go with xsi. SI modeling tools/workflow are a lot smoother than max. But on the other side max has a lot of third party plugins/scripts that are helpful. I cant speak of maya as I havent "really" used it.
As mentioned, comes down to personal preference. IMO though, I see Maya more as a organic/freeformish kind of modeling app, and great for rigging and animation. While Max to me seems more like a structural and precise app. Still, both can be used to create modular assets with the same precision and vice versa. And there's…