I'm currently dealing with a G5 Dual 2.3GHz Mac although the move to 8 Core Intel Mac is inevitable.
Right now my workflow is shoot
I have 2 8GB and 1 16GB for 100 minutes.
I hook camera to G5 and use XDCAM XFER tool to hard drive.
I back up the XDCAM .MOV to DL-DVD
I edit XDCAM EX but I'm switching render code to ProRes
Once I get Intel Mac I'll be using Clip Browser to back up the cards original data instead of the .MOV to DL-DVD
At 35Mbps VBR I'm fine with about the same Hard Drive space I've been using for DV.
I do wish someone would make an Express card reader for MacPro rather than having to use slower USB.