I've been experimenting with CS3 Extended.  It is unfortunate that it can't (especially considering the high price tag) generate UV maps on models.  I think it will be very useful for editing textures and seeing immediately how it looks on your model.  For instance say you wanted to add a tattoo to a body texture and exported your model to PS CS3, you can open the texture layer,  add the tattoo, save it to update your model and get immediate feedback.  Unlike in the past when I had to import the map in Photoshop, guess how it would look export it, load it into my 3D application, retexture the model and if it didn't look right repeat the process all over again.  When you get something you like you can export the texture map by itself and then reload it into your application.  Since this will only work with mapped models I was wondering it I could load a texture map template to my model as a texture and then start from scratch--I'll have to see.

I think that where CS3 Extended will shine is in the ability to composit 3D models into pictures, I think it's rendering and lighting tools too limited to do portrait work, but will suffice for many things--like adding props and models to photos and better integrate them into a picture.  I do find it rather annoying that rendered objects in CS3 Extended don't cast shadows, but I can add shadows with Alien Skin Eye Candy.