[delic]

No, we are not :). In my lab at the university, we strictly use Apple G5 because PC workstations are simply not able to handle the computational load. It's not just hardware but also the operating system. With photography, I do raw conversion on Mac (Capture NX) and subsequent tiff-to-jpeg conversion with touch-ups on PC (Photoshop). The reason is that I have CS2 running on PC only.
I don't think you need a Mac so long as you have a good monitor. In fact NX runs faster on a PC. Best wishes,
Hakan