I use Gentoo exclusively for last few years on my laptop, no Win boxes at home at all. I wouldn't say compiling everything from sources is kind of interesting thing, but Gentoo unstable is one of a few distros where I can have up to date KDE and other apps. And in the same time, unlike Arch, it is stable enough as maintainers don't, for example, change default python from 2 to 3 overnight.
In my opinion Linux on desktops still lags behind windows for average user. I'd put KDE between XP and WIn 7 in terms of overall usability. One of reasons to have it at home is when you develop a lot of scripts for linux and want to have the same environment on your development box without using virtual machines. Another reason is that with linux you're pretty much safe from troyans and exploits, as they are being written mostly for Win and OSX.
Upd: I use Debian on my servers and vps's and have no idea why people still choose CentOS for their servers. C'mon guys, Centos' default repository lacks lots of necessary stuff, such as nginx. You just have to plug in 3rd party repos and turn your system into a mess. It has RHEL as upstream with all that lawyers stuff related to huge corporations - such as the case when CentOS had crippled OpenSSL without elliptic curve algorithms because there were some obscure patent problems. Why not Debian? Is it because CPanel works on Centos only? There are other panels, and anyway, vanilla ssh console is almost always faster way to do things.