Hi, Brian - I've got the same iBook as you. I have two OWC (Other World Computing: http://eshop.macsales.com/catalog.cfm ) portable 40gig Firewire drives which I use for backup. I like the portables because they draw their power from the Firewire port, and therefore do not require an AC adaptor. Plus they are very small, and can easily be tossed into my carrying case. I bought my second drive a few months ago, with the 8mb buffer. My first drive has the 2mb buffer. The 8mb buffer is definitely faster than the 2mb for copying large, contiguous files. I don't think there's much difference if the files being moved are small and/or fragmented, because the speed slowdown there is head-seek-time, rather than transfer speed. But if you're dealing with large files (in my case, dozens of audio files of digitized lectures, averaging about 250-300mb each) the speed difference is VERY noticeable and appreciated! There is one other important consideration if you're using a hard drive for backup, in my opinion, that nobody seems to ever think about. If you have a large, bulky hard drive, which requires being plugged into an AC adaptor, you'll wind up leaving it sitting on the desktop next to your computer all the time because it's a pain to unplug it and stash it somewhere safe. So, if your house ever gets burgled, or a small offfice fire happens, or something like that, you'll lose both your computer AND your backup! With the portable pocket-drives, though, it just takes a moment to unplug it from the firewire port and stash it safely in another part of the house entirely for safekeeping. That way, if the computer gets stolen, well, your backup is safe and sound at the top of your linen closet, or wherever you put it. I NEVER leave my backup drive in the same room as my iBook once my backup is finished. The reason I have TWO drives is because I travel a lot. So I make TWO backups of my iBook drive, and keep one with me in my computer case, and put the other in one of my checked bags. That way it's unlikely I'll lose both drives at the same time. I've assembled my own drive a couple of times, and it really isn't very hard, but I don't bother doing that any more. Drives are cheap enough now, and the warranty issue is important enough, that I just buy them already assembled. Cheers - RJLaue