Elena Novaretti has produced a superb PNG icon patch for OS 3.5/3.9 which lets you use PNG icons, like those in MorphOS.
Update: For a quick comparison: MikeB's
classic icons and
png icons with patch installed.
Download
PowerIcons.
Have tested this on a A1200 060 with Mediator and Voodoo 3 and it ran very well.
