We're expanding and we need to pick up a quadcore g5. Any advice on memory? I'm on a dual 2.7 and we put in 4.5 gigs of memory and its quick.
Also, has anyone used any preview cards (specifically BLACKMAGIC) with the quad?
We're a post house who does lots of animation/editing.
I'd go with at least 4gb's again. If you run multiple animation/editng applications at the same time, then you might consider doubling that to 8gb's of memory. I don't think you need to go beyond that for most pro work at this point (that will change in the future). I highly recommend you get your memory from Crucial as they are the OEM for many computer manufacturers (including Apple) and it will be much more cost effective than getting it directly from Apple. They are a good company that stands behind their products.
I prefer the AJA Kona cards myself, but you can pickup a BlackMagic card for cheap and they both should get the job done. Make sure you get the PCIe version of whichever you choose, and not the PCI or PCI-X, as they will not work in your Quad.