Now I am not sure what you plan to do with this new computer, but when considering whether to wait for intel or not, what you must consider is that at the moment most apps for mac is PowerPC only so they would run through Rosetta. This is fine if you don’t do any sort of graphics or video, or need to run obscure 3rd party mac apps. In terms of which is better, well g5 Quad Core PowerPC or any g5 is pretty good. Intel will take over the mac market eventually, but thats a long ways off, you should be safe doing either. Its more right now what do you need to do with the computer and how urgently do you need the computer.
Best of luck
Simon Carlson-Thies