Windows one would think, even if you clean it. You'd have to use FireWire Target Mode to run Disk Utility on it I believe. As far as I'm concerned, flash drives would prove to be more stable anyhow for the iBook, and I know they work for it, so why do this? If you plan on opening the iBook up and installing a new drive, a flash drive or two would be worth the effort, even if they're smaller than the other HD, which has a rotating disk like the iBook drive. Then you'd have to replace the Windows laptop drive, and that's no fun either. Bypass the WinBox and save yourself some trouble. Flash is just better and more ideal for the iBook.
I hope you consider all of the ups and downs before you do it ;-).
I'm itchy to tinker with my iBook once again, and have the materials to do it. Here's the plan:
I have a Windows laptop with a 37GB Samsung Hard Drive, 9.5 MM in height, 2.5inches standard size, 5400 RPM, 8Mb buffer, etc etc etc. Very quiet and been used for just over a year. Here it is: http://www.samsung.com/au/products/harddiskdrive/harddiskdrive/mp0402h.asp
In my iBook is a 10GB toshiba hard drive, 9.55MM in height again, 2.5 inches, 4200 RPM, 1Mb buffer, and very noisy to say the least. Here it is: http://www3.toshiba.co.jp/storage/english/spec/hdd/mk1016.htm
In case you haven't yet guessed, I want to pull the Samsung drive from the Win laptop (that I hardly use anymore) and pop it in the iBook. Then I'm thinking later I will either get a bigger hard drive for the Winbox (or I will use BMF's idea and get Flash card storage) and put Vista on it. But that's beside the point. Does anyone see any problem here or have any caveats? I have not researched properly, yet, whether OS X and 9 are compatible with the drive I intend to put in here, but I will research that. I mainly want to swap it in because of the increased storage size (it will be able to hold all of my music and programs etc etc) and the higher speed. I shouldn't think it will get too hot, although, these clamshells appear to have no fan, and just rely on heat dissipating naturally.
Lastly, if anyone can suggest any free utilities which will let me ghost my drive's current contents onto my external, and then restore onto the new drive, that'd be great. Saves putting all the data back on here and getting all the updates etc etc.
Thanks all, looking forward to hear some suggestions!