I've finished the upgrade to Biscuit. With a new case, motherboard, and CPU, it seems like I ought to rename the server, since but for the hard drives and optical drives, this new rig is really a whole new computer. The final setup is an Antek 300 case, Coolmax 750w power supply, AMD Phenom II X4 CPU, Biostar T-series ATX motherboard, and 8GiB of 1600MHz DDR3 RAM. Feeling really good about all of it. Ran memtest and some CPU benchmarks and everything's hooked up and ticking along nicely.
Tomorrow's task is to get the hard drives set up more like the old configuration (right now only a single 500Gb drive is connected), and to migrate the old users to the new setup. For Biscuit users, I will say tentatively that we'll be 100% online late tomorrow night. This is a very good thing. Later, space cadets.