as long as the Quadro's your running are PCI Express cards I can't think of a single reason why they wouldn't.
just download and install the proper Quadro drivers for your OS and you should be fine.
I don't have a Quadro, but a Geforce card, GTX 285 mainly because I game a lot, but do tinker and mess with some products like Carrara 6 Pro, Daz Studio 3 Advanced 64 bit, Bryce 6, Hexagon 2, Photoshop, GIMP, Premiere Pro, etc from time to time, learning to use the software while creating 3D backgrounds and videos for my own use (my modeling talents suck, but I do love setting premade models in scenes, and shading changing aspects of models sometimes too.)
but am also running an i7 920 based system for that stuff, 750W non modular Corsair, only 3GB RAM for now, but will be upgrading to more down the road, running Windows 7 64-bit Release Candidate, 24" 1920x1080 LCD, several hard drives (32MB cache Server Drive for my Windows drive, and a 2x 250GB RAID 0 setup for the apps, video and stuff)
but to answer specifically, no Quadro is not for xeon systems only, you can run a Quadro on any system you want, AMD mainstream CPU's, Opteron Server Chips, Intel Mainstream, enthusiast and Server CPU's, heck, if you want to can even couple a PCI Quadro with a lowly Via C3 or C7 MiniITX/MicroATX based CPU system if you want, they will run together, albeit CPU performance will suck, but it will run.
just make sure the proper OS drivers are installed and you should be fine.
the Quad cores and HyperThreading on that CPU will make CPU rendering much faster too, which is why I bought the thing myself, otherwise I would of stuck with my older Socket 775 Quad core and waited for the Core i5's to of come out (a month or so ago). unfortunately I don't have any programs capable of GPU rendering other than OpenGL Preview Windows, so my GPU goes to waste, even for a gaming card, when running those apps.
but thankfully to programs like BadaBoom and Nvidia's CUDA when it comes to encoding video to other formats, it just flies through the process in seconds or minutes...
badaboomit.com
not sure if you've seen that, but if and when what ever Quadro you get, if the Quadro supports nvidia's CUDA capabilities, you might want to check that out for a handy program to use, since you mentioned a lot of video. was able to convert an entire 5 minute video for Youtube in seconds with the GTX 285 with this program, at least the trial version.
hardware
prices 
). That could be an option down the road once the Geforce starts to show its age.
