I would max out the memory in the iBook... I know that all the memory sold at
www.mohawkmem.com is rock solid. They also have a 100% satisfaction policy where if the memory EVER goes wonky, you get a replacement chip from them (provided something that will work is still available). That policy follows the computer, not just you. I have a pair of 512MB chips in my TiBook from them, and they give me no problems.
If you don't see exactly what you need/want, give them a call. They also get other things besides memory.
Oh yeah, their return policy is very nice. You call them, provide some info (to prove that you purchased the memory in question from them, can't blame them there). They then ship out a replacement chip, along with a postage paid box for the one you are returning. Not a bad way to do things, at least in my book. If you live outside of MA, then you only have to pay shipping (ground is about $8 or so). If you live in MA, then you know all about sales tax.
Oh yeah, for a while at least, they were selling the 5GB iPods at well under what you could find them elsewhere. Something else to check into if you are in the market for them.