Can you describe in a little more detail what kind of processing and visualization you will be doing?
Are you SURE you need double-precision for processing and visualization? I understand the need to try to have everything as accurate as possible, but if your output is an 8-bit image, it does not make sense to do FP64 calculations and then losing all the accuracy downsampling to 8-bit for output anyways.
Also, I work in image processing field as well (more specifically: bio-imaging analytics), but we run some pretty sophisticated segmentation, registration, and tracing algorithms. Unless you are analyzing thousands of those images in one go, you are better off putting your money into faster CPUs which will speed up everything else.
Tesla is Quadro without all the display output hardware. They cost roughly the same too, so for all intents and purposes, you may as well grab a Quadro.