Josh said:
If you're in graphics and rely on Adobe/Macromedia heavily, there is no reason to get an Intel yet. It is much more effecient, cost and work wise, to continue using a G4 and definitely a G5.
At the very least, upgrading from a G4 to a used G5 would be wiser right now.
You're really missing the big issue here. If an Intel iMac is a good solution for you, there's no reason to get a G5 instead of an Intel iMac.
If you're well funded, if you need a full tower for expansion and gobs of memory then get a G5 tower. if you want or need a 24" or 30" monitor (and more importantly if you can afford one) then get a G5 tower. The dual-core towers are still very nice machines, they hold two internal drives, you can put in a Fibre Channel card and a CAD video card, you can put in 16GB of RAM.
If, on the other hand, you've got a tight budget and 20" resolution is fine, at least for now (you can span two monitors on an iMac), then the Intel iMac is a much better deal. You can get a very nice 20" intel iMac with the 20" lcd for about the price of a low end G5 Tower (without a monitor). The iMac will be smaller, it will be plenty fast, it will use less power (and cost less to run and to cool.. computers dump energy into the work environment after all). The iMac will run all of your software fine now, though it won't run PPC native software as well as a G5. Of course, the intel Mac will allow you to finally run Windows only apps reasonably.
Finally, Intel is the future. PPC will be supported for a long time, Apple's still selling software maintenance contracts for PPC machines so we have at least two OS updates and patches for those through the life of the 3rd major OS update. That doesn't change the fact that the future is Intel. The machines are very fast. All maintained software will ported Universal eventually.
I think the important distinction here is what can you afford and what do you really need.
If the imac form is acceptable..
If there aren't huge memory or video requirements..
.. then I suspect an intel iMac would be a fine design machine.
On the other hand, if you're doing 3D work which requires the fastest video for live rendering and gobs of memory AND your software has to run as fast as possible.. then an Intel iMac is likely not appropriate for several reasons. Most likely, an iMac will never be appropriate AND you'll want to run your software natively (PPC on a PPC or wait until your apps go Universal).
ffakr.