For the past 5+ years I've used blackbox as my Linux window manager/desktop, it's very clean, fast, wonderful as far as not hogging memory is concerned but you have to do the application integration yourself - for gnome applications you may need to make sure dbus is running, for amarok you need to start the sound backend yourself, you need to check periodically for security updates manually, rather having them presented to you.
So yesterday while not wanting too much pressure and recovering from a bout of asthma, I took the easy path and tried KDE4 and was fairly impressed, you could forget about the nuts and bolts and just run the application. There was though a feeling of being constrained - it knew what you wanted and you had to fit things around it. When I found it had stolen the Ctrl w key - not idea what for - and no doubt there's a way of grabbing it back for emacs where - for me - it is incredibly useful - I decided I wanted something else.
I'm currently trying the Mandriva integration of fluxbox - slightly different to how it appears in Ubuntu but the integration seems good, rather than having to - in blackbox - do it all yourself. I'll see how it goes! It still seems to come with the kde sounds - click on a tab in firefox or pan and I get blasted with a 'cute' noise, no doubt I shall eventually find the off switch!
Here's a screenshot:
pretty similar to blackbox, minimal just the background a term window and the toolbar, really except that I'm trying it with hiding the slit:
this is a sort of dock which contains applications useful in many contexts - so there's mainly gkrellm giving a snapshot of machine activity, facilities for taking screenshots and email notification. I'm also running wmbiff to tell me how full are my various (mostly) spam bins.
The toolbar gives me current state of the music player and will show when when there are security updates/application upgrades available.