what most people don't realize is that Windows is a copy-cat of Apple's earlier OS's. IMHO a Windows OS will NEVER be superior to a Mac OS. the architecture is different and there's no 3rd party hardware to foul stuff up
it's just amazing what you can accomplish when all the internal hardware relates to itself
I should mention , in fairness, Mac OS X is based simply on UNIX (BSD from NexT Computing to be exact). So, Apple copied from a decades old OS to get OS X
Nothing like tried and true UNIX to base your GUI on.
I should also mention I have many years (10+ now...sheesh!) expeirence with Solaris 7, 8 and 9, AIX 4.x to 5.3, Windows NT 4.0 Server, 2000 Server and 2003 Server (of course not as much time on the newer ones).
Currently, because I'm prepared (firefox/thunderbird/etc etc), my personal XP laptop and XP workstations (2 of them) never go down or have spy ware/virus issues. Of course..I've prepared them and keep patches up to date, but not too up date , all automated. Our 2000 and 2003 servers have excellent uptimes as well, due to the same diligence. Of course for any enterprise level (thousands of power & simultaneous users) type application, don't use Windows servers. Linux is also decent for small scale stuff.
Oh, and to be really fair, I hostly beg anyone to claim to that the iTunes/iPod GUI client is a "good interface". How did that slip out into production?!