Tiny Core Linuxis still going strong (http://www.tinycorelinux.net/). They're now up to three images, all built on the idea of running out of RAM with a 3.0-era kernel. The Core image is CLI-only and weighs in 8 MB; TinyCore adds a GUI/WM interface at 12 MB; and if you have RAM to burn you can opt for the 64 MB CorePlus image which is the only one that starts up with wifi set up.
It's a kick to play with. It's just amazing how fast a minimal distro can be running out of RAM. Even when you load it up with Firefox and a bunch of other apps you're still only looking at a few hundred MB.
Linux is my main and the operating system I use (Laptop, Phone, Server and Media Center). It is fun to see other people trying to hack Linux to run on obscure or minimal systems but as a daily user I think the biggest achievement would be to run Linux more efficiently on a regular machine and not on obscure system.
Scientific Linux really isn't a special-purpose distribution. It's just another Red Hat clone like CentOS. (Some people claim that it's actually a superior alternative to CentOS.)
It's as special as Edubuntu. It may be based on RH (as Edubuntu is based on Ubuntu), but it's prepackaged with lot's of software for scientific usage (the same way Edubuntu is prepackaged with educational software).
It's obvious that some distros are more special-purpose and some of them can easily be configured/converted for everyday usage.
Springdale Linux (previously PUIAS Linux) is another RHEL 6 clone but they do provide a repository that contains some computational maths software. That repository is not installed by default, and can be used with the other RHEL clones.
It tries to combine free software into a suite for creative people.
Driven by the fact that there are so many cool applications out there, but most people do not know them,
openArtist tries to be a complete package of creative software.
Its cool to see the OS starting to be configured specifically around certain applications rather than the other way around.
How soon until apps live in their own specific OS environments on USB sticks and my "main OS" is just a hypervisor to run them? The return of the cartridge. Everything old is new again.
parted magic looked interesting, but doesn't seem to add a coherent interface to everything. has anyone who has used it also used yast's partition manager (from opensuse)? if so, how does it compare? because i'd love a simple, standalone tool (one that i could use on other linuxes) that had all the functionality of yast's pm (eg. it can create encrypted llvm volumes over raid, for example - something that's available in the opensuse installer but seems to be beyond many other distros).
I've used it a lot and it works very well. However, at present I'm using stock Ubuntu 12.04 with the studio (mostly music production based) applications loaded through standard apt-get means. In the past Ubuntu Studio packaged a kernel built with Ingo Molnar's low-latency patches, but the stock kernel is good enough for real-time, low-latency production these days. Other than having most of the applications that you'd need packaged for you - a valuable service for new users - I'm not sure what Ubuntu Studio brings to the table for experienced users.
It's not a great article.
Other people have mentioned Geexbox and XBMC which are useful media centre distributions.
Slitaz is a cool minimal distribution, with excellent internationalisation. (It's amazing what they fit in to such a tiny package.)
Tinycore / microcore are great minimal distributions, but I don't know how much they're being developed at the moment.
Exherbo looks suitable for masochists. (http://exherbo.org/)
Arch / Gentoo / Linux From Scratch are great for people who want to learn Linux or who know exactly what they want.