http://www.desktopbsd.net comes with KDE. For the record bsd is not actually linux, but it runs most of its binaries, while the opposite doesnt happen.
I've used myself Windows from version 1.0 in 1986 and up to XP/w2k3. Overall I was never impressed with the work done by MSFT and always having in mind the size of the company. Last week I checked a full preview video of Vista and again I was kind of dissapointed. MacOs as Diesel said is great OS and keeps getting better for the simple reason it introduces various innovations that are on the right direction. With Windows you can't tell all their changes are actual improvements. I predict over the next 10 years new OS slowly but steadily will gain popularity among users.
Have you heard the One Laptop per Child project by Nikos Negroponte? It's not a project anymore, rather a reality and comes with an OS for kids called SUGAR which was developed by Red Hat team itself. It's going to be distributed to millions of students all of which they'll more likely be introduced to linux principles before even getting to hear about Windows.