I have been using Ubuntu as my only OS since 2006. I am on the Ubuntu Forums under the same user name. In the past, I have tried all three of the Ubuntu DE's (Gnome, KDE, XFCE) but I always found myself back with Gnome.
However, with the recent changes (Unity, I'm a Mac clone), I will probably be moving to Xubuntu sooner or later. I gave KDE one more try recently, but I find that I am too firmly entrenched in the GTK way of doing things.
I am a musician, and my long term goal is to learn my way around Pro Audio using Linux. Most folks in that world default to Macs. I want to avoid the expense and vender lock-in that comes with using a Mac.