End-of-2007 State of the Union

2007. What a year. Ubuntu cranked out two more solid releases, sub-$500 laptops flooded the market and undermined Microsoft's influence, and 3D desktop effects continued to improve. The DistroWatch charts were invaded by Texans, and several new distros appeared on the scene, while existing ones (Mint, Sabayon) joined the ranks of the Top 10. And what a Top 10 it is...
Gentoo: What a nasty year for Gentoo! First, Daniel Robbins comes back to join the amd64 development squad, only to leave in disgust a week later. The development process over there is devolving into anarchy, and it's not helping their release schedule: The first release arrived three months late, and the second (and last for the year) is already even later. Expect Gentoo users to flock to Paldo and Sabayon- which will help Paldo make it into the Top 10.
Mandriva: Another year, another two solid releases, and another Corporate Desktop. Mandriva continues to tweak their software selection, improve 3D effects, and make their distribution even faster. But it's showing signs of age- both releases were two weeks late, and little else changed except artwork, eye-candy, and the usual upgrades. Mandriva seems built to last, but it will be overrun if development keeps up at this pace.
Slackware: Slackware is still Slackware- sort of. Another release this year, but this time, they actually upgraded some key packages. Linux is at 2.6.21.5 (a step up from 2.4.33.3), X made it to version 7, and Apache is from the 2.2 series. Slackware, like Debian, is used as a base for countless other distros (Zenwalk, Vector, Wolvix, etc), which means they'll all finally include some decent software.
Debian: They actually had a release this year! :-) Etch turned out to be a solid, fast, customizable release, and a solid base for distros like Pendrive Linux and Dreamlinux. Ubuntu is still clobbering them, but they still have a huge following, and rightfully so. Sid remains the most up-to-date Linux distribution.
Sabayon: Now that they have Daniel Robbins on their side, they might start replacing Gentoo... Oh, wait, they did that already. Never mind. Sabayon is still a distribution of its own, with its own (overstuffed) software selection and exceptional hardware support... Or, at least, it was until they introduced the "Core Install" in version 3.4, which installs a minimal base that can be built upon, Arch-style, using Portage or Equo, Sabayon's new binary package manager which one-ups Gentoo in yet another way. Ouch.
Fedora: Version 7 was a letdown. Version 8 was outstanding. Version 9 is going to be awesome, now that they're back on track with a stable system (even with all the bleeding-edge software) and have an extensive feature list planned for it (including KDE 4). Bring on RHEL 6!
Mint: Touted on Digg as "the new Ubuntu", this Ubuntu fork is faster, more complete out of the box, and (arguable) has better artwork. All this in addition to the mintTools including file sharing (mintUpload), a customizable control center (mintConfig), an update manager (mintUpdate), and more, all open-source. It's still a toss-up as to which distro has cuter code names, though.
openSUSE: 10.3 turns out to be the simple, straightforward release the last few versions were supposed to be, albeit 10 months after 10.2. It also turns out not to be for hobbyists (go with Fedora in that case). They're still adding features, though, and the brand-new one-CD live/install hybrid option is worth all the effort they put into it.
Ubuntu: Ubuntu continues to be Ubuntu- minus the number-one spot on DistroWatch, and plus three new derivatives (Ubuntu Studio, Gobuntu, and Fluxbuntu). Also added are revolutionary new X-fixing tools (graphical, no less), a codec wizard that blows Fedora's new Codeina out of the water, hardware driver management, and- finally- Compiz Fusion effects. W00t!
PCLinuxOS: Somehow, they manage to steal the number-one spot on DistroWatch's charts with only one release throughout the entire year (and the next one'll have to wait until long after KDE 4 is out later this month). According to DW's Ladislav, the results are not rigged, and so one has to wonder where all those hits are coming from... Anyways, PCLinuxOS 2007 brings a face-lift, huge speed improvements (it's now one of the fastest distros that's not source-based or based on Slackware), Beryl (which is out of date), and enough codecs and programs (Frostwire, anyone?) to keep you off Apt for weeks.
From Ubuntu 7.10,
The Distrogue.