Generally, I agree with fuchsdh; however, depending on your use of Cinema4d and After Effects (where Adobe is now shifting AE's 3d rendering chores to C4D Lite), you might want to consider getting an Nvidia GPU, such as a GTX 780 Ti or 780 3G [or 6G if you want to do 4k graphics] if you do substantial, large format rendering. For one of them, I'd recommend that you scout out on Ebay, using a search such as the following for a used one :
http://www.ebay.com/sch/i.html?_odk..._trksid=m570.l1313&_nkw=gtx+780+6+GB&_sacat=0 . Having an Nvidia GPU will allow you to take advantage of CUDA rendering which can substantially decrease your rendering time in C4d with a GPU rendering assist from (1) Octane Render [
http://render.otoy.com/features.php ] [GPU only renderer], (2) TheaRender [
https://www.thearender.com/site/index.php/features.html ] [hybrid renderer that can use either CPU(s), GPU(s) or CPU(s) and GPU(s) simultaneously] or (3) FurryBall [
http://furryball.aaa-studio.eu ] [GPU only renderer] . Currently, I recommend them in that order for use with C4D, based on their current state of development. The reason that I didn't recommend a Maxwell is that those 780s are uniformly faster at rendering than the 9xxs that fall within your budget. If you go this route be prepared for having to install an extra powering source because these cards require both an 8-pin and a 6-pin PCIe power connector. Here's how I help to power mine:
http://www.fspgroupusa.com/ecommerce/retail-psu/booster-x5.html .