FYI
I just dropped by Fry's Electronics here in San Diego & found out that they have 4GB memory for the iMac (don't know if it's the same for Mac Pro) for $54 after online rebate (you pay $94 in store).
They also have seagate 750GB external hard drives (usb2.0) on sale (for today only) for $119. They're not fire wire, but still good for another backup drive.
I'm far from a tech genius, but I think these are pretty smokin deals. Hope this helps. Have a rad weekend everyone.

I personally wouldn't trust FRY's memory in a mac - I'd much rather spend the $100 (still a smoking deal) and buy 4gb of RAM from http://transintl.com - but then again, I don't have an iMac, so I can't even get RAM that cheap...