Hmm, I started on Gentoo around 2004. In 2007 I used Ubuntu for awhile. I then wanted to go back to Gentoo so I used Sabayon for awhile. I started using Arch when KDE4.0 just came out. So that would be in 2008. Haven't switched since then.
I first started tinkering with Redhat Linux because I wanted to play Quake3 in a new OS, and Nvidia's 0.9 Linux driver had just been released. I was running a custom built desktop with dual PII 300 CPUs OC'd to 450 and a Geforce 256.. a week later I was jumping with joy when I finally got the driver compiled and got Quake3 to work .. LOL .. those were the days.. soon after I got ahold of Redhat 6.0 and the rest is history..
The first distro for me was Redhat 8 -- which I installed on an old computer in order to turn it into a firewall. To be honest, I had no idea what I was doing at the time, I just followed some tutorial. Scary command line. Some time later I did however install RH 9 on my own computer, and there my journey really began -- first RH, then Fedora Core 2. Anyway, it didn't take long for me to get enough of RPMs and having tried installing Gentoo on other (and other people's!) computers I did the switch too. Been running Gentoo on my own computers since then (approx. 2005)
Best Linux 2000. Yup, Linux distro with that name existed. It was terrible but the manual that came in the box was awesome.
I still have it and have its manual. Its very detailed. Fstab has scared me a lot. Later reading Orelly books didnt help much either - it was too technical, too scary. Ubuntu made me to switch, now I run Gentoo and actually hate Ubuntu a bit(mostly for apt limitations; non-comparable with portage).