Tiger seems to like my old iBook well enough. I have it booted from the drive in my G5 at work, and it certainly isn't any slower than Panther was. I don't know if it's actually any FASTER either, but certainly not a loss.

Like I said before, you shouldn't have a hard time running it on your iBook, once you can get it on there. The installer is not gonna like a machine with no Firewire.