I first gave Linux a try in 2002, when I set up a spare machine for the express purpose of messing around to learn. I tried getting a desktop environment running on Debian (potato), and after pulling an all-nighter only to get to a grey screen with an 'X' for a cursor, I gave up on that approach. I subsequently gave Mandrake (now known as Mandriva) a try, and was immensely impressed with the ease of installation. Ironically, I didn't even end up using the desktop environment much at all, but started poking around with apache, proFTP, samba, etc., and learning how to run a Linux server.
A couple years later, I took the plunge and replaced my GUI Mandriva install with a Debian Woody non-GUI install, for the role of a home server. The install went fine, and I promptly understood all the hype about apt. I started to feel confident enough to recommend Linux for some in-house servers at work, where I got my first experience configuring and compiling a kernel, falling in love with apache2 (compard to 1.3), and hosting email and DNS.
I'd poked around knoppix a few times in the early-to-mid 00's, but had pretty much made up my mind that "Linux is for servers, Windows is for desktops." Ubuntu changed that. My second experience with LOTD (Linux on the desktop) came after I was forced to relinquish my company laptop around the end of 2005, which meant that I was compelled to promptly purchase my own. There was already great buzz around Ubuntu, and being based on Debian, it already had favor with me, so I gave it a shot, and dual booted
my new IBM Thinkpad T41. (Ubuntu was at 5.10, Breezy Badger at the time.)
I probably should have blogged about it more at the time, but my recollection is that my main problem was battery life, which was pretty poor in Linux back then. (Hardware/drivers weren't really a problem at all, since Thinkpads generally have good Linux support.) If I ran plugged in, I was content to use Linux, but when I needed to be on the go, I'd boot back into Windows. I thankfully had some good support in IRC, who turned me on to NetworkManager before it was part of Ubuntu by default, among other things, which was pretty spectacular compared to the prior situation. (It's one of those things that "just works," so if you tried it for the first time now, you probably wouldn't even specifically notice it.)
I started using the Linux partition more and more, and upgraded through Dapper, Edgy, Fiesty, and Gutsy, growing more and more usable with each upgrade. Among other things, battery life improved considerably, to the point where I'm now roughly on par with Windows for longevity. (On my new Vista laptop, Hardy actually beats Windows slightly.)
Until ~April 2006, though, Windows remained my primary platform (i.e., on my desktop) ... until my desktop inexplicably died one day (but that's a story for another thread). I fell back to a free P3 733 MHz desktop for a bit, which was running Ubuntu for development purposes. However, that ended up being slower than my laptop, so I bought a USB keyboard and started using my laptop as a desktop for the next couple months ... in Linux. This experience was a turning point, when I really started to understand that Linux had, overall, reached a point of general usability for me.
I eventually replaced my desktop, and around the time of the Gutsy (7.10) release, bit the bullet and put Vista and Ubuntu on my desktop. I'll admit, I used a fresh hard drive, in case I wanted to go back to XP, but thankfully that didn't happen. Since that day, I've booted into Vista approximately four times total: three since I had to reboot for Linux kernel updates, and decided to download Windows updates / service pack, and once to play Portal. Aside from that, I've been completely Linux-based for almost the past year, and upgraded to Hardy this past weekend (after they finally pushed the kernel CGROUP scheduler to hardy-updates).
Three side notes:
3. I bought my (not-super-technical) girlfriend some laptop of craigslist last summer, when she was heading out of state for a ~2.5-month project. In addition to reloading it with a fresh copy of XP MCE 2005, I loaded Ubuntu, and encouraged her to give it a try. I admit that I did some configuration during setup that she probably wouldn't have been able to do, and she had the "advantage" of already being familiar with Gaim/Pidgin, Opera, and FireFox, but she said she was able to use it just fine, with the sole exception of booting into Windows because the iPod w/ Nike+ web integration required iTunes (and I wasn't going to try to get her to run it in Wine). I did also find it interesting (but kind of logical, in hindsight), that she initially expected programs to just be programs ... not specific to Windows or Linux. e.g. "Why can't I run iTunes in Ubuntu?" "Because Apple doesn't consider Linux users a valid market segment, so they only made versions for OS X and Windows." "Oh. That's dumb." ... or "Why isn't Gaim/Pidgin installed in Windows? I have it in Ubuntu." "Well, it comes installed by default in Ubuntu. You have to download it and install it manually in Windows." "Oh. That's dumb."
2. I continue to run Debian on my servers (one at home, three hosted, and several at work), but hadn't reconsidered it as a desktop platform since my wonderful experience with Ubuntu. I installed it on my desktop on a USB hard drive two weekends ago, and am pleased to report that its desktop installation experience has vastly improved. That said, it still lacks some niceties of Ubuntu that will probably keep me from switching (in addition to laziness).
3. OpenOffice isn't perfect. For "Word Docs" that are very layout-critical (e.g. a résumé), I still rely on MS Word.