Openbox is one of the more popular lightweight window managers. It can be used as a standalone solution or as a component of the LXDE, the Lightweight X11 Desktop Environment. The default look of Openbox is rather minimalistic, but it is a good basis for building a custom desktop.
The default look of openSUSE's openbox
Fortunately, the internet is full of resources and tutorials for customizing the look and feel of Openbox. Here are some of the more informative pages I've found:
- Openbox documentation
- Openbox FAQ
- Urukrama's Openbox guide
- Openbox in Ubuntu Wiki
- HOW-TO: Install, Customize, and Configure Openbox (lots of options)
- Configuring Openbox V2
- Kmandla's Feisty Openbox on 1Ghz Pentium III, start to finish
Themes for Openbox can of course be found in the usual sources. See, for example, the following:
Can you recommend some other sites?