iMac or G5?

Hi everybody.

I need somebody's advice. I work with graphics, photos and large files.
What would you buy (for approximately the same price)?

- PowerMac G5 (used) - 1,8GHz*Dual Processor - 1.8GB memory - 160GB HD

or

- iMac 20" (new) - 2.66GHz Intel Core 2 Duo - 2GB memory - 320GB HD

Thanks!!!

I love my iMac.

how in the world are you getting 1.8 gigs of memory with a mac pro?