I have a dual-boot Ubuntu/CentOS laptop that my daughter has been using for the last few years. I'm about to decommission it (is that the proper terminology, decommission?) due to the fact that the laptop pretty much falling apart. Even so, I'm in the process of updating both the CentOS 5.2 and Ubuntu 10.04 installations.
While I do have a Linux/Windows dual-boot on my main laptop (the 2010 Lenovo G555), these days I don't stuff more than one Linux or BSD on a single machine. (For the most part, dual-booting is just not worth the trouble, though I reserve the right to change my mind.)
On the CentOS/Ubuntu dual-boot, the Ubuntu side started out as Xubuntu and eventually morphed into GNOME-running Ubuntu that survived an upgrade from 8.04 to 10.04.
Now that I have the laptop -- the old 2002-era Gateway Solo 1450 -- plugged in, I decided to update the CentOS 5.2 side first, just to see if it would work after years of being neither booted nor upgraded. It's in the process of downloading and installing some 350+ packages and is taking its own sweet time despite a very fast network connection.
I'd love to be able to use CentOS on the desktop, but I very quickly run into problems with finding packages for software I want and need. OpenShot, Gpodder, even Geany -- it's just too much effort to find packages built for and subsequently maintained for CentOS/RHEL.
Fedora, of course, doesn't have this problem -- you can get just about anything in its repositories. But you need to upgrade/re-install every year or so due to the six-month release cycle. For the record, Fedora supports releases for 13 months.
Truth be told, I usually run Debian on this kind of hardware. It's consistent, reliable and generally lasts three years (two years as Stable with a year following as Old Stable, though I tend to upgrade either after the Testing freeze or soon after release).
The Ubuntu LTS is also a great choice for hardware you're going to neglect, i.e. not run every day and upgrade whenever you get around to it. That's even more true now that Canonical is promising five years of support not just on the server but also on the desktop.
The Gateway Solo 1450, running a Pentium 4 at 1.3 GHz and now equipped with 512 MB of RAM, is the subject of hundreds of articles on my old but not dead blog. The screen is failing, slowly, but failing nonetheless, one of the two USB ports is broken, and the Cardbus/PCMCIA slot has been broken for some time. It's 10 years old.
I'm getting the 2002-era Thinkpad R32 ready to replace it. Yes, it's the same age as the Gateway, but it does have a better-working screen, three working USB ports and a working Cardbus slot. And I think I have some extra memory lying around to boost it from 512 MB to 768 MB, if only I can find it. (Little parts like laptop memory sticks tend to go missing, I've found.)
While Ubuntu 10.04 runs fine on the Gateway (surprisingly enough), I don't want to foist Ubuntu 12.04's Unity or Fedora 16/17's GNOME 3 on my daughter. I've tried a bunch of distributions over the past few months, and I thought I would settle on Xubuntu 10.04. It's an LTS, and she likes Xubuntu. But graphically I detected a little sluggishness on the Thinkpad, and I ended up liking the even-simpler default installation of Lubuntu 10.04. Though not an LTS, it is a very polished implementation of an Openbox/PCManFM-running LXDE desktop.
By "simpler," I mean there are fewer extras in Lubuntu as compared with the Xfce-running Xubuntu. Xfce is a pretty big ecosystem these days. Not that there's anything wrong with that. But in this instance I wanted to start out as sparse as possible and add the applications from there. I don't want it to be command-line sparse, or LXDE-on-Debian sparse. I wanted something with a working NetworkManager and display-manager. That's where Ubuntu and its derivatives, Fedora and its spins, Mint, CrunchBang, Bodhi and countless other distributions excel. (I could also figure out how to install and configure NetworkManager on Debian systems that don't ship with it, but that's another matter. And no I'm not particularly fond of Wicd.)
Not to go off on a tangent or anything, but I find that I like Debian a lot more when I install and run the project's default desktop environment, which happens to be GNOME, as opposed to the default Xfce or LXDE installations (and I've run the KDE default as well, though my memory of it is more hazy).
The "lighter" Debian default installations don't include the GNOMEish bits that almost everybody else adds as a matter of course. I don't think there's anything wrong with that, per se, but it can take a while to get the default LXDE or Xfce desktop in Debian where you want it. Not so with the GNOME default, which is pretty much ready to go after installation, something that surprised me greatly in the Etch era when I first tried Debian and found it remarkably similar to Ubuntu yet much faster on my always-older hardware.
Meanwhile, the CentOS install is still downloading (and now installing) the updates. I still need to get the /home files out of the Ubuntu installation and copy them onto the new Lubuntu system.
Changing distros is OK when you don't have any files, but once you do, it becomes more of a pain. And that's why I tend to look for releases I can stick with. I get the testing out of the way before committing to a "lasting" installation and data migration.
That's the theory, anyway. I did a full Xubuntu installation on the Thinkpad, then added the lubuntu-desktop package. Once I saw how well the latter environment worked, I started over with a Lubuntu ISO image and now have a "pure" Lubuntu system. I removed the applications things I didn't think we needed, then added all the educational/game packages that are on the to-be-retired Ubuntu 10.04 system.
I expect (and hope) to see a lot more attention paid to Xfce, LXDE and Enlightenment in the wake of Unity and GNOME 3. As I've written many times, you don't feel a slow desktop on newer hardware, but on some of these old systems I run, you can really tell the difference between a light and not-so-light desktop environment. If you just want to use your computer and not worry about the "new" desktop environments that throw out the old and replace it with a not-terribly well-tested new, there are alternatives out there.
I'm not saying I won't go from Lubuntu to the full Ubuntu with Unity for the Thinkpad in the future, but for now I'm going to give LXDE a try and see if it meets with approval from my little girl.
CentOS update: Are you wondering how the CentOS upgrade went? It took hours, but it all went smoothly. I now have a fully up-to-date CentOS 5 desktop. I don't really need a CentOS 5 desktop, but going years between upgrades and having it all work is somewhat remarkable. I don't recommend you "do this at home," or at work. But if you have an old CentOS/RHEL/Scientific Linux box and want to upgrade it after years of neglect, it just might work.
Ubuntu update: I also managed to update the Ubuntu 10.04 installation. I didn't upgrade to 12.04, though I may try that at some point. I know I mentioned it above, but it bears repeating: Ubuntu 10.04 with GNOME runs pretty well on this 12-year-old laptop. I wonder if GNOME 3/Shell and Unity are as "speedy" on such old hardware.