Those Toshiba drives are lemons. I had the same 30GB in an iBook G4 (mid-2005); it lasted only two years. The guy who sold me a new one acted as if the drives had a fairly high failure rate.

I've had bad luck with other Toshiba drives as well--both hard drives and CD-ROMs.

I think I had a Hitachi installed in the iBook when I gave it to my cousin at Christmas. Of all the current drive manufacturers I have had the best luck with them.