Hmm, I think my first ever experience was with Mandrake. I would have been 11 or 12. I remember looking for longhorn leaks, and the website I found them on also had a Mandrake support section. So I checked it out, and tried it but the internet wouldn't work on it. After that I tried various distros and broke them all.
Currently Arch is my go-to Linux that I have running on a plethora of virtual machines (and primary on my PI) at home and work.
My first experience with Linux was somewhat similar: I tried Mandrake. A friend told me it was the easiest distro to use for beginners. KDE was supposed to be super-simple to use. Unfortunately, I didn't really take the time to understand how things worked, got frustrated, and moved back to Windows XP.
I was encouraged to try Ubuntu 9.04 by a coworker at my first job during college. That time I installed it on my desktop, and began dual-booting with Windows Vista. Over time I started using Ubuntu more and more, but I never uninstalled Windows because I still wanted to play PC games. I was very happy dual-booting Windows and Ubuntu on my desktop and laptop for several years. Although I used Ubuntu the vast majority of the time, I still occasionally booted Windows to play games (mostly on my desktop). When Canonical decided to switch to Unity, I moved to Debian 6 because it still had GNOME 2. Since that time I have retired my desktop and bought a new laptop, which has never run anything but Debian natively since I wiped the Windows 7 installation from the factory. I have been an extremely satisfied Debian user for several years.