In January, I bought a Dell Mini 9 netbook with Ubuntu Linux rather than Windows through the Dell Outlet for ~$200. It’s a pretty stripped version, with only a 4gb SSD, but I was tired of lugging my 7lb Inspiron through airports and I’d been inclined to try a Linux machine anyway.
It has worked out pretty well, though a bit sluggish. The Dell version of Ubuntu (Hardy Heron, a Long-Term Support version) included a quick launcher bar broken down by category:

I found it generally more useful to go into the “classic desktop” view, however, since the quicklauncher wasn’t particularly suited to finding files. Dell recently started updating the version through their repositories (Linux sponsors provide “central” locations for updates) rather than the Canonical one, and I was hit with two updates in one week. The first seemed primarily about the battery manager and was welcome. The second sped up the machine, but somehow reorganized the “classic desktop” that I’d been using into something much more like the quick launcher, with a single drop-down menu (Windows-like) rather than the Apps/Places/System trifecta that traditionally rules Ubuntu. Furthermore, the power button disappeared from the screen, hidden (again) in the drop-down menu.
Trying my limited patience, I initially searched for a way to undo the “improvement” on the Dell boards. Time to try the “Netbook Remix” edition that is directly available from Canonical. It took about 20m to install off a USB key, and what a visual improvement:

It’s smaller (on the drive) than the Dell version, it’s faster, and it uses the limited screen size much more efficiently. I should have done this months ago. All the software is more up-to-date (Open Office 3.0 rather than 2.1, the latest version of Firefox, etc) and it’s overall prettier.
I’m not a hardcore Linux nut, but I appreciate the open-source software movement and use a variety of open-source programs already on my Windows work machines (Firefox, R, 7-Zip). The Ubuntu flavor is improving quickly, with new releases every 6 months. I don’t know that it will ever be as big as Windows or Apple, but for those willing to try it out, it’s already “there” in terms of usability, and it will make you start wondering why anyone pays for operating systems currently. I’ll probably upgrade the SSD in the near future.