Khronos
Because you are experienced w/ Photoshop, I recommend that you investigate every modeling app you can before deciding on one which best fits your workflow, as PS can help along in the texturing arena, and 3D models can assist in PS compositions.
C4D is great. There's also LightWave, 3D Studio, and Maya if money is of no concern. If you're on a budget, Blender and Wings3D are free. Download demos of every program to get their feel. I've been through Extreme 3D, Carrera, and trueSpace before settling on Maya.
Questions to ask of your 3D app:
+ Does it do both surface (nurbs) and solid geometry? Surface is good for easily building organic surfaces, but solid modeling allow for Boolean operations (addition, subtraction, ya-dah-dah).
+How's the rendering quaity, or will you need a separate rendering app? Many modeling folks use Poser or Vue 'cause the rendering unit in their modeler sucks.
+How's I/O? Will the modeler import obj, dxf, 3dmf, and other popular 3D formats? Does it export renderings with alphas? Is tga, tiff w/ alpha, or psd supported?
+Is it extensible? Is there a community of plug-in developers?
+Does it do animation?
+Does it do physical simulations such as wind, particles, and fluids?
+Are metaballs supported? This feature is good for creating quick fluid and organic shapes.
Happy hunting! The jouney's worth it! I "graduated" from a physical drafting board to computer graphics to 3D to 3D animation. It keeps me young!
My Best,
Gary