A lot depends on what type of scenes you want to render.  Right now, for pure terrain, I think Terragen 2 has the edge.  It's still in beta but some of the scenes I've seen are so close to photo-realistic that it would be very difficult to approach with Bryce or Vue.

I'm not a big believer in  "all-in-one" applications (modeling, terrain generation, texturing, etc.) but then you can make some great scenes if you have the talent and persistence.

There are some very nice programs that are reasonably priced that one can make a nice suite from: Silo, Blender, Make Human, Gimp, 3D-Coat, Terragen, Genetica come to mind.