Just upgraded to a MacPro 2.66 with 2Gig of ram and an extra internal 500GB drive on Bay#2 that I plan to use as scratch disc. Coming from a G5 single with 512 ram I feel like I am in heaven, for the first time I can see my HDV tapes from the HV-20 being captured in real time. Editing in FCE and IMovie 8. I don't feel I'm ready for FC Studio 2 yet.

Anyway, since I'm doing more now in HD, I've considered adding another 500 Apple drive to Bay#3 or..... adding an external FW 800 or even one of the new Quad interface drives with Sata hook ups. I know that for those I will need and extra PCI express card to get the Sata speed, but then again the Apple drives are already eSata. My experience with external drives have been limited but not very good. Right now I have an external LaCie 160 that died and cannot recover anything from it, even using DiskWarrior.
I've considered Quads from OWC, G-Tech, Wiebetech and others or none and just go with the propietary Apple drives.
Portability is not an issue since I don't plan to move them anywhere.

What would you suggest, I'm sort of a newbie at these things
Thanks
Your input will be appreciated.
Luis

If you've got an additional 500gb HD in your Mac Pro there shouldn't really be any other need for another one in bay #3 or an external. Externals are fine if you don't have the room in your case but they take a few extra seconds to spin up if you haven't used them in a little bit of time. (can be annoying after a while)