other than for C4D, it sounds like you really don't need a fancy build whatsoever to do what you need. C4D is not exactly one of the highest-end rendering programs, and as this is the case it is heavily CPU dependent by default. That being said, you would do fine in this case with a mid-range GPU and a higher-end CPU, such as a 4770k in theory. This is if you plan to use the program as it is, without any interest in performance
HOWEVER!
C4D does support third-party plugins that allow CUDA support on particular rendering engines within the program. If you're serious about the rendering that you do, then you would know that hardware-accelerated(GPU) rendering is VASTLY superior to CPU in every single way possible. In fact, GPUs are dozens of times more capable in any type of workload(especially compute workloads) than CPU's are. This is why it is always desirable to use programs that are coded for CUDA or OpenCL hardware acceleration. You can do the same work in fractions of the time it would take for the CPU to do by itself when it is being heavily loaded due to a weaker GPU. Open a 10,000x10,000 Pixel image in Adobe Photshop and modify it heavily with and without hardware acceleration. You'll see the difference in speed with the CPU by itself and then with the GPU acceleration. It's incredible.
Why am I telling you all of this? Simple: if you plan to be serious about any sort of rendering, then you would use these plugins to enhance your experience in whatever task you are working on. If this is the case, your CPU would become irrelevant, and instead of forking over tons of money in a high powered I7, you can go to a decent I5 and build with a GTX 770/780/780ti/970/980 to do the work for you.
Your experience with the 300$ GPU and $150 cpu versus your experience with the $300 CPU and $150 GPU would be night and day. consider the software and it's technical points before making irrational decisions.
Anybody can come in here and tell you that an i7 + GTX970 or GTX 980 is going to be good for what you do, but I'll bet half of these guys have no idea why they're coming to that conclusion.
Go with a midrange CPU (I5) and mid-high end GPU(use the extra funds to buy your CPU cooler, OS, accessories, and so forth), and thank me later. Not only will you have the better performance for rendering, but you'll have a fairly good gaming build as well.
also, since you asked...at this point in time more than 8GB of RAM is not necessary, although it won't be long before programs start needing more. 8GB will do you fine for now, hell it is enough for anybody right now. Just be aware that programs are getting hungry these days, so don't go buying four 2gb sticks to fill up a four-slot MOBO just to save a few dollars. Keep room to upgrade later on without having to buy all-new ram.