Hi tgun, welcome to the Macintosh Users Group!
I have experience with a Dual 800Mhz G4. It was the model that the Dual 1Ghz replaced. I highly recommend the dual processors if you do work in Photoshop. Some other Adobe products are also dual processor compliant, and there are more to come. The Dual G4 processors always toast the Pentium 4 in Photoshop tests.
Mac OS X is fully compliant, so that means even the Finder will be faster than a single processor machine.
According the chart below, taken from
this page on Apple's site, the Dual 1Ghz is 78% faster than the 933Mhz in Final Cut Pro 3.
Hope this helps. Let us know if you need any more info

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[Attachment Pruned on 03-14-2003 at 01:18 PM by Alex]