$100 bones is a lot for a video card for a 10 year old Mac.
Thanks for the "reality check." I'm a bit torn on it, as it does seem like a lot of money to put into the computer(as much as I paid for it), but do want the best. I'll keep my eyes on Ebay-I found the Mac edition card you referenced, and will watch it and see where it goes.
That card should work for you. A bit much for a flashed one. You may want to research prices of a Mac Edition X800 before committing to buying that one, unless you really want dual DVI ports and no ADC.
Any conceivable situation I see with using dual monitors on my G5 would require dual DVI outputs, as there is not an ADC-equipped Cinema or Studio display that really appeals to me for the type of work I'm doing on this computer. Every ADC-DVI converter I run across seems to be $25-$30, so it would seem worth the cost difference to me to not have to worry about this.
This isn't a really pressing problem in either, and if I can get the Mac edition X800 that's up on Ebay now for a decent price, I'll probably just go ahead and get it and deal with the ADC-DVI problem later.
Thanks again to everyone for their help on this! It can get a bit confusing trying to research some of this stuff, and I appreciate you all taking the time to talk me through specific combinations of hardware.