I have the said powerbook and while it's a nice machine, it isn't *that* much faster than your ibook. If you're going to be doing a lot of graphics work or burning dvd's then it might be worth the upgrade. I would suggest maxing out the ram in your ibook (640 mb) and waiting until the next revision or two before upgrading. You would, however, notice a difference with the 1 ghz powerbook.