I installed LXDE on top of Mint 7 XFCE and it works great. However, some of the LXDE component applications (notably lxpanel and lxterminal) have old versions in the Ubuntu Jaunty repositories, with less functionality than the current versions, so I downloaded the DEB files for the latter from the Debian sid repos and installed those. (I don't know if that was the brightest move, but it worked!
) I'm still hoping for an LXDE CE of Mint to see the light of day, someday, but so far this works well for me.
As far as other distros go, I haven't seen much with LXDE that impressed me. I found the Lubuntu beta quite underwhelming — just stock, out-of-the-box LXDE on top of Ubuntu, didn't even bother to replace the LXDE logo on the menu button with the Ubuntu logo or anything. Same was true of an LXDE edition of OpenSuse that I tried. MoonOS is nice, but it's basically a rebranded Mint, so you won't get anything there that's different from what you'd get from Mint with LXDE. The artwork is lovely, though! PCLinuxOS has an LXDE version, and it looks all right as far as I can tell from the live CD, but I couldn't install it on my system because my wireless won't work with it, and I've only got a wireless connection on my computer, so that was a deal breaker for me. (I posted about this on the PCLOS forums, and asked why it should be that my wireless works out of the box with just about every distro that I've tried except
PCLOS, and was basically dismissed with "Wireless support depends on the kernel. Next question...") I read that the latest version of Knoppix uses LXDE, but I haven't tried it yet. I don't know how well Knoppix works as a desktop OS installed on a hard drive, though; I've always thought of it more as a run-from-the-CD thing.
Also, if you're looking for a light distro, have a look at Crunchbang. It's my other favorite distro besides Mint. Like Mint, it's built on an Ubuntu base and has all the multimedia codecs, etc. running out of the box. The interface is a bit different, but it's like 2/3 LXDE. By default it uses tint2 instead of lxpanel, so it has a task switcher and notification area but no menu; in place of a panel menu you simply right-click anywhere on the desktop to get the Openbox menu (LXDE uses Openbox for the window manager, but stock LXDE does not make use of its menu capabilities) which has been highly customized in Crunchbang. The other major difference is that stock LXDE uses the filemanager, PCManFM, to draw wallpaper and icons on the desktop, while Crunchbang turns this off by default, using nitrogen to draw the wallpaper and eschewing icons on the desktop. Crunchbang is really light and fast, and works well on older hardware. I'd highly recommend checking it out if you haven't already.