It's fun to see the results here. You know just by looking at some of them -- like Redhat, not Fedora: and SUSE, not openSuSE, that some of us have been doing this for a while!
I started in April, 2001 -- and no I didn't know this was actually Linux's birthday month -- and kept on going. Now I'm on openSuSE 12.3; started with SUSE 7.1.

The first distro I used was Ubuntu 6.06 LTS, beginning in June 2006. Currently using Linux Mint 13 Maya (MATE DE) on my desktop computer (P4 2.80 GHz, 1GB RAM, runs very fast on this 9-year-old machine) and Ubuntu 12.04 LTS on my notebook (Intel Celeron 847 1.1 GHz x 2, 2GB RAM)

Although I did put Red Hat (I believe it was 4, still have the discs somewhere, and it came with a book, too) - the distro I actually stuck with and used productively was Edgy-Eft (Ubuntu). I defected (sort-of) away from Ubuntu when Unity came out - and there were stability issues, too - to Mint... still very enamoured of that distro!

My first Linux distro was Freespire, but it wasn't right for me and I moved to Ubuntu within a month.

Slackware. It was a pretty early version. I got it sometime around the mid-90's. The floppies were included in a book I bought. Over the years I tried other distros but always came back to slackware. When Patrick Volkerding dropped gnome and went kde only, I switched to Fedora core (I hate KDE). Lately I've succumbed to the dark side and started using Xubuntu. It's fast, simple and easy to use.

Mine was LinuxPPC 2000. It ran like shit on my scsi-based Mac, but I was fascinated. Had to make it work somehow. Linux is a habit not easily abandoned.

my first distro was centos

The last version of Mandrake, I was the hero of the desktop crowd. I had tried Red Hat earlier that I borrowed from our server guys, but I never could get Red Hat to work on our desktop machines. It's never been anything but Linux on my machines. From Mandrake/Gnome I went to Mandriva/KDE and finally Slackware/KDE. I panicked when Mandriva went broke and I tried many distros but finally decided upon Slackware. I'm basically lazy, so I don't like change. I'm an old school computer user, that's why I like KDE, it just flat works out of the box. I'm 58 years old so that puts me at a small lead over the Windows and Mac whiz kids. The whiz kids keep asking me how I do so and so and I tell them that it's all so simple with Linux.

Mandrake 9.2

My first Linux experience was Red Hat 6.0. A friend had recommended it to me. I had no problems getting it installed, but never was able to get it on the Internet, or get the mouse working. Experimented with newer Red Hat releases, and other distributions such as Turbo Linux, SOT Linux and Knoppix, even tried FreeBSD. Eventually I came to Debian. Sarge (3.1) was just released as stable. Only used Sarge for a short time though before quickly moving to Etch (was still in testing) as it had better hardware support. Around this time I was no longer using Windows as my primary OS. I had used Debian Etch (testing) for months before eventually moving on to Sid. I still use Debian Sid as my primary OS.

I still have the copy my friend made for me of Red Hat 6.0

Apart from a shoer stint in wubi, LFS was my learning experience, but it wouldn't count I guess, because to build LFS you need another distribution

I'm very interested in what this poll implies. It seems more users started off with more hardcore versions, with Slackware leading, and Mint not even making it into the picture! I guess that's because the majority of this community are power-users and not the usual everyday user. Or perhaps that's because the Ubuntu and Mint users are more geared to getting support from the forums in the distribution's site...

Re hat linux. All went much more smoothly than we aticipated. We installed it on our firts laptop (a dell inspiron 7500).
We had heard horror stories about instalation, but i was wonderfull. We still have that laptop, dunno what to do with
it.

I'd just like to say that although TurboLinux WAS my very first distribution, I had quickly switched to Mandrake (which became Mandriva). I learned a lot about the command line and how linux does things with turbolinux, but I spent a great deal more time USING mandrake/mandriva

Not listed in the poll above, but I started with Linpus Lite! Which I replaced with Ubuntu Netbook Remix after a very short time.
Linpus Lite was the Acer branded version that came pre-installed on Acer netbooks. Hopelessly out of date and stripped to the bone!

when i first read about linux back in 2008 i tried almost every distro. as a noob i only felt comfy with mandriva, very noob friendly despite its lack of some important packages and difficulty getting things to be built on it. i soon realized its good only for getting your feet wet, more than that you need to switch. i switched to pclinuxos after that and kept using it for about 2 years, now using fedora as i do lots of development. i still recommend it for newly comers to this world and tell them when they hit the wall you ll be able to pick a distro of your own.