I suppose it depends on which revision G3 ibook you have as well. For instance, I wouldn't even wanna run OS X 10.4 on my iBook G3 300Mhz... so those are the things you might want to consider. An earlier version of OS X would be more prudent for performance reasons.

Wrong, there are drivers, they're just built right into the OS because the hardware are fully manufactured by Apple only. Also, Apple includes by default a lot of drivers that you don't need, to ensure that for the normal user, when they plug something in, it'll just work.

Windows on the other hand is a software company that does not make hardware, therefore the hardware manufacturers have to write their own drivers to ensure their hardware can run on Windows.

If you were to buy a third party peripheral, chances are you'll need to install OSX drivers before you can use it anyway. Printers are one example although Apple does already support a lot of printers out of the box, and provides even more drivers via an optional install from the OSX install DVD.