Our entire server farm is running 8.04 LTS, but i'm reluctant to upgrade without the Xen supported in the repositories. My desktop I just upgraded to 10.04 and its damn nice and I'm loving the new color scheme.
My other box at work runs Karmic. I might consider upgrading to Lucid sometime soon. But I'm still a Mandriva guy. As polished as Ubuntu is, its relative lack of solid, powerful and user-friendly system configuration tools keeps it from being all it could be in my opinion. It annoys me to have to regularly search online forums for the correct way to perform what should be a routine task. Both my computers at home run Mandriva and will continue to for the foreseeable future.
DSL (dang small Linux) RULES! Only a ~70mb installation... and you can run all apps from a USB flash drive! I kid. I only use Linux at work, but we're a RedHat shop. I'd love to maybe one day get into the Desktop Linux... in 2050... I am a LAMP user, though.
[WORTHLESS BUMP] After starting work at my new job, I thought I' wouldn't ever see Linux again because where I am they are a Windows only shop and only have a few specialized Linux machines which we don't access. Well, after a while, we ended up thinking a solution to one of our projects was to use a web page and there were some PHP scripts available, so I get to use Linux again, but this time it's on UBUNTU. This SwoLy is happy to report I'm back on Linux. http://www.youtube.com/watch?v=T9hSpijwWCY
I only use Windows at work. At home I have an old Fujitsu Lifebook running Ubuntu and my new Chromebook, running Chrome, of course.