At the risk of starting a huge flamefest, I actually think this is a fun topic to discuss. Everyone has their favorite distro, and I'm interested in finding out what it is that people like about what they use, why they like it better than the ones they don't use, and what they use it for in the first place. There are a lot of distros that I haven't spent much time on, mainly because I don't know enough about what they offer to have a compelling reason to do so.
I'll start it off.
My Linux distro of choice is Debian.
What I use it for:
Mainly servers. I prefer OS X on the desktop. /me ducks :P
What I like about it:
- Minimal base install size. This is great for machines like routers.
- Entirely community developed and supported. This is something that you either love or you hate. Sometimes waiting for concensus can be frustrating. The wait is worth it for me because I know that when Debian does a release it has been widely tested and hasn't been rushed out the door to meet some marketing deadline.
- Non-commercial. Debian's not gonna go out of business, get bought out by another company, decide to change names and business models with no upgrade path, etc.
- Takes free software seriously. Debian makes it very easy to run a system of free (as in "libre") software, keeping the non-free components in a separate branch that users can include if they desire.
- Runs on almost everything. Debian supports something like 11 architectures. I like playing with somewhat random hardware, and it's nice to be able to run the same distro on everything.
- APT. Portage is cool, but just with the base-install on my Blade 100 I ran into two circular dependency issues. This does not happen with APT.
Why I prefer it to other distros:
The only distro that I have used enough to actively dislike is RedHat. RedHat was the first distribution I ever used, and I can't ever say that I liked it. As soon as I felt competent enough to try out other distros I went looking for other options. I run Yellow Dog (basically RedHat/Fedora for PPCs) on one of my Macs, and I don't like it either. They just feel too abstracted from the "Linux feel" of things for me. They give me a Windows-ish vibe that the command line is an afterthought, and one should configure everything with GUI tools. I don't like the installer - it's really easy to get a desktop install done, but you end up with 20 editors and 5 browsers and 6 mail clients, etc..
Out of everything that I've tried, Gentoo is probably my second favorite. It's just a cool idea, and it runs pretty nicely on sparc. Documentation is excellent, and the developers (at least the sparc ones) are very helpful. Install can be minimal, though slow ;-). I'm very impressed by the hardened Gentoo project.