I found out that the firmware on late 2004 G5 models don't support drives larger than 250G.
I have a (2005) Mac G5 and I just installed a new Western General 1Tb hard drive (SATA 7200 3.5) in it, I was running Tiger OS prior to the hard drive going bad. When I boot using the OS disk and pull up disk utility, I can't see the new hard drive so I can mount. Before I bought the new hard drive, I had the machine tested @ the genius bar and they assured me my h/d went bad and everything else was functioning ok. Is there a step I'm missing? Any help would be appreciated.