I've been using Debian since 2001. I started with the stable distribution, but pretty soon switched to testing and then unstable, which I happily use till now (I think since 2003). Recently I decided to get some packages that I needed into the distribution. And it's really easy, one just needs to create the package and go to mentors.debian.net and some Debian developer will upload it into the archive.
When it enters the Debian unstable, it automatically gets to Ubuntu and currently, Ubuntu is the most widespread linux distribution. Thus it's very convenient to just upload one package and a huge part of linux users can easily install it with one command (in a recent poll, 44% of all desktop users are using Debian or Ubuntu).
I should have become involved with the Debian developers much earlier, because it allowed me to get to know many great people -- all developers I met are real experts in linux in general and Debian in particular and I learned a lot from them. They are sorts of people that know how to get things done so it's a pleasure to work with them. Simply anything, that bothers me on my system and I would like to have fixed, I just either fix it myself or with the help of others, then send the patch to the maintainer of the particular package, he uploads a new revision and that's it. The next day all my debian systems are fixed.
Information about configuring various packages in Debian.
To use any of my packages, that are not in the Debian unstable yet, use my repository http://debian.certik.cz/.
See also my page at http://wiki.debian.org/OndrejCertik, that contains information about what I do in Debian.