Coming to GNU/Linux
I've started using GNU/Linux and Ubuntu in April 2005, beginning with HoaryHedgehog.
I remember how impressed I've been by the Live CD, the beauty of Ubuntu and the number of available (open source!) applications at my fingertips.
After comparing Gnome and KDE for several days I've decided to go with Kubuntu on the desktop. At the same time I've rented a (web)server, dist-upgraded it from Debian woody to Ubuntu (which required several attempts) and deployed a quite sophisticated environment there (following different tutorials, reading and learning a lot).
Contributions to Ubuntu
I'm subscribed to bugmail for several packages and read what apt-listchanges tells me from the changelog of updates. When I then see that something has been fixed in Debian/Ubuntu's development release, which is likely to be a top crasher, I look for previous bug reports and duplicates, and propose a StableReleaseUpdate for it (e.g. bug 141516 or bug 131526).
On 2007-11-15 I've been approved for the ubuntu-bugcontrol team, having collected already more than 5000 bug management karma points until then.
I care about all packages in general (most of the fixes I've provided have been for packages I've not known and used before), but especially I'm interested in server applications (Apache, lighttpd, PHP, Python, Postfix, MySQL, duplicity, ...), the K Desktop Environment (KDE) and a whole bunch of other programs I'm using. A more detailed list can be found at my ohloh.net stack.
I like to help out in the QA process, by triaging and providing patches where possible, so that every Ubuntu user gets the smoothest user experience as possible. My current impression however is, that it takes too long after a fix is provided until it is available to the average users. Fortunately, the source code is available and everybody is free to fix or ask somebody to fix it.. - but still, I believe that the process can be improved, e.g. by throwing more developers at it..