Humanized has a good article on one particular aspect of usability in the Mac Vs. Windows dispute.... Luxury Computing talks about some of the challenges in doing some simple things in both Mac and Windows.
After going through the same three dialog boxes, the wizard appears yet again; this time it’s found a “HID-compliant device”, and I have to go through the same song and dance, after which I get yet another wizard for a “HID-compliant device”.
Another "what tool for what toolbox?" debate, though some usability issues are more like using a hammer that randomly smacks you in the thumb by itself (Ok, so I'm not all that good at analogies :)