Ubuntu
I’ve been using Ubuntu for about three years now. Previous to Ubuntu I had used Debian for a couple, and Slackware from my early days as a Linux user.
As a Debian user, moving to Ubuntu was really a piece of cake. My only reason for moving away from Debian is the fact that Ubuntu has regular (every 6 months) releases. The software repository is current and constantly evolving. It’s OK in some environments to be stagnant for a few years between releases — but when you’re a developer, it’s fairly important to have the ability to upgrade easily on a regular basis.
The Ubuntu community is also one of the best as far as Linux users go. Extremely helpful, and mostly courteous. Ubuntu is easy, smooth, and makes me tingle inside.
More stuff, when I think of it.