I have a dual-boot Ubuntu/CentOS laptop that my daughter has been using for the last few years. I'm about to decommission it (is that the proper terminology, decommission?) due to the fact that the laptop pretty much falling apart. Even so, I'm in the process of updating both the CentOS 5.2 and Ubuntu 10.04 installations.
While I do have a Linux/Windows dual-boot on my main laptop (the 2010 Lenovo G555), these days I don't stuff more than one Linux or BSD on a single machine. (For the most part, dual-booting is just not worth the trouble, though I reserve the right to change my mind.)
On the CentOS/Ubuntu dual-boot, the Ubuntu side started out as Xubuntu and eventually morphed into GNOME-running Ubuntu that survived an upgrade from 8.04 to 10.04.
Now that I have the laptop -- the old 2002-era Gateway Solo 1450 -- plugged in, I decided to update the CentOS 5.2 side first, just to see if it would work after years of being neither booted nor upgraded. It's in the process of downloading and installing some 350+ packages and is taking its own sweet time despite a very fast network connection.