It would be nice to have both computers. For upgrades, you might want a G5 desktop and a 20" Apple LCD monitor. For iBook 17 inches monitor, it would be nice to carry around with you. It's tough choice.
I have a dual 2GHz G5 desktop and a 20" LCD monitor. I love them. The price is for sake, and wanted to get over with it. It is very important that you should buy an AppleCare Protection Plan for a 3-years warranty. The AppleCare comes with a TechTool CD.
See Nusentinsaino's post that has the information for you to make a decision. Good Luck.
