When I was a kid I got obsessed with Linux, but my family only had one PC in the living room. After an attempt to set up Windows/Linux dual boot where I messed up the partition table, my parents banned me from tinkering with it. Luckily I discovered Knoppix and other live distros, which allowed me to boot into a safe environment to play around in.
I remember also hosing the bootloader somehow on my first try of Linux, luckily my personal desktop so no collatoral damage! After that I always had a CD wallet thing with copies of sysresccd and supergrubdisk and others (including I think an old knoppix cd from a linux magazine).
When I first started going towards Linux I tried, in this order:
* Puppy linux, because I liked puppies.
* College linux, because it was for education, and I was in secondary school, and college sounded fancy.
* Adriane Knoppix, because it's what came up when you did a web search for "knoppix download" -- that was interesting, if you didn't know, ADRIANE is for blind people.
* Whoppix (which became Whax) -- because I could actually find the download.
* Backtrack linux (because that was apparently better than WHAX)
* Slackware, because backtrack was based on this and "only script kiddies use Backtrack".
I did the same as you, tried to keep things to liveCDs but I always got the urge to install them, so would do it periodically until everything broke. This also meant I had to deal with whatever was broken (usually wifi).
One thing I remember very fondly though, which isn't a linux, is the leaked Geek Squad rescue CD... I'd give a decent chunk of change for an updated one of those..