Right now I'm the happy owner of vue and photoshop, all my modelling atempts are done in Blender which is a very powerful 3d suit you can achieve almost everything with. Expect steep learning curve. Im just modelling and texturing. In fact you don't need anything else for 3d maps. A 2d programm like Gimp or PS for post work would be good.
Terrain generation is done with world machine 2, a procedural approach guideable by defining areas.
There are free versions of WM2 Vue, Blender is free. So give it a swirl and get your feet wet. Looking forward to a new 3d approach