Except that Carrara 6 is more than Poser 7 plus advanced rendering tools ... it's more like Poser 7 with a built in terrain generator (Bryce/Vue) and Modeler (take your pick of any, even free).

The only major things missing from Carrara that would be present in a Poser/Vue/Modeling App combination are the cloth room and the setup room. We don't know what's coming in teh future.  Carrara has its own rigging features so that's a non-issue for those who want to stay only within Carrara. With so much pre-rigged content out there that comes in fine, the only ones that would need rigging tools are those who develop content specifically for Poser.

In Carrara 6, you can add content, model original content, and create realistic scenery all in one application, without having to worry about import/export issues, scaling, and all of the other stuff you have to consider when you transfer from one app to another. Add to that Carrara's shaders (which meet or exceed Poser's advanced shaders), and dynamic hair (which from the examples looks absolutely stunning).

If I had my money on the line, and didn't  already have apps that didn't do content handling, scene generation, and modeling, at this point my money would be on Carrara 6 instead of Poser 7+/Vue or Bryce, and a modeler, simply for the convenience of being able to compose a scene, develop new content, animating, and rendering all in one application.