Also, do you think I could get away with replacing the G5 with the 2.6 GHz MacMini i7 quad core intel ?
Yes and no.
Sounds like a dumb answer but the main reason for the NO bit is the standard OS.
It will be Lion or Mountain Lion, both OSs are not supported by Apple using FCE and users have mixed results from mostly working to hardly working to won't go at all.
FCE 4 and 10.6.8 is the sweet spot.
I think 10.4 is probably a drag factor with you current slowness.
The YES is using FCE 4 with Snow Leopard if you have it or can get it.
The next thing to consider is the newer FCP X that is compatible with the newer OSs.
The mini does have a Thunderbolt port so that makes it expandable for editing work.
Thank you so much for all the help Al . You are a champ .
I guess I could use my wifes 10.6 instal discs and upgrade hers to Mtn Lion ...
I think when I upgrade , FCP X is a steal and will get it too .
Right now , I am happy that I can get reliable / consistent Blu Ray burns now that I burn a disc image first .. Thanks to you and Meg !