From their press release, you can tell how much 3D Studio Max 5 has a focus as a game developement tool. It's looking ahead with hardware shaders:
"it's already DirectX 9 enabled, allowing you to easily add custom hardware Shaders that reflect the world you need to simulate in real time. And you can easily export the visual realism you create to real time 3D environments"
..and better polygon modelling abilities..
"The power behind UVW Unwrap has been unleashed to give artists ultimate control over their mapping coordinates, and Polygon Modeling has evolved to make 3ds max 5 the most comprehensive modeler on the market."
..there are a tonne of other improvements and features, so if you want to find out more, read it here!