Colleagues and I are currently exploring options to compute and visualize x-ray tomography data that we have been collecting. There are several freeware programs available that all seem very good, and we now need some hardware. We've been advised to get the best videocard possible, with RAM and CPU being secondary to this (as well as needing heaps of hard drive space, but that isn't really an issue). I'm guessing that a MacPro is probably in order, though am curious whether a high end iMac might be able to do it. If any other users, esp. scientists visualizing data, have advice about an appropriate system to buy we'd be grateful. I've always been a Mac person, but am considering getting a Windows machine in this case, because it seems as if Apple seems determine to cripple it's computers with inadequate video cards. Please contribute your $0.02! Thanks. p.s. does anyone have experience with whether employees at an apple store would be willing to install 3-rd party software to test how different mac models perform??