I remember a similar thread some time ago, but I thought I would contribute again.
I first heard of Linux while I was at university as a mature student, but didn't try it out because someone suggested it wasn't all that functional. In any case, I wasn't ready to risk losing Windows in case I couldn't complete my assignments using MS Office tools.
Following graduation, I found that my version of Windows 95 was collapsing like a wet wedding cake. The Internet was a fairly new concept to me, and I thought that viruses and online attacks were the exception rather than the rule. How wrong I was! I didn't even have a firewall; I was so green...
I was left with a problem. I need computer skills for my job, but I didn't have the resources to buy MS Office. At that time, like a lot of post-grads, I was quite poor and needed to make some cuts. Still curious about Linux, I bought a copy of a street paper called 'The Big Issue' (UK members will know all about it) and saw a review about a book called 'The Hacker Ethic' by Pekka Himanen, with a forward written by a certain Linus Torvalds.
The book made a lot of sense to me, because it appealed to my natural radicalism, and suggested that work should be done for joy, not just for pay. This idea is still following me around today... I like to play around with technology, and I like to explore new ideas. Linux partly fulfills that need.
I found a copy of Mandrake 9.? attached to a Linux mag. and tried to install it on my old box with no results at all; it simply wouldn't do it! Strangely, I knew it would work sooner or later so I decided to build my own computer. This was a challenge for me, as I had never attempted it before.
After a lot planning (too much in fact) I ordered hardware through the post and got building. Eventually I had a bootable box with no OS. Like most 'newbies', I tried a frightening array of Linux flavours including Slackware (actually I found this one dead easy to install), and most of the other mainstream distros. There were many trials and tribulations: the path to *nix Nirvana is rarely smooth, but persistence is always rewarded.
Today I'm back to using Mandriva (as it's now called). I might try others as I feel inclined, but I'm too busy doing other stuff right now.
I'm not 100% Windows-free because I have to use it at work, but I don't have it at home. If I've learned one thing it's, 'Don't be afraid to try new things. Make mistakes, but carry on and you'll get there in the end.'