A little late to the party, but you can also get an ATA 133 PCI card and not be limited by the built-in addressing ceiling. A multi-function card like the Sonnet Tech Tempo Trio that gives you USB 2, FireWire, and two IDE channels is a good choice because you can use just one of the three precious PCI slots and get multiple connectivity options.

Peace,
Drew
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Power to the PowerPC!