That depends on whether you want to boot OS8/9 or OS X. There are cards that can boot both but the ones that can boot OS8/9 are Mac-only (Sonnet Tempo SATA for example) and more expensive. It's possible to flash a generic Silicon Image-based card with firmware that will boot OS X.

I have a Rev A and it will only work with the original stock hard disk on the IDE channel. Doesn't matter if the other drives I try are older, newer, bigger or smaller. It'll corrupt like crazy.