I'll stick with kde, and run it on a computer powerful enough to handle real graphics.
I like KDE but its a fat-fat WM. Ever since they started to become the feature king (by competing with gnome) they have gotten into bloat issues..
Oh well one of the nice things about Linux is a selection of WM's
Ditto.
But it's lightweight.
If you're recovering a P200 laptop with 32MB of RAM to be used for very light comm duties, FVWM isn't a bad choice.
That said, it wouldn't be my choice. I've got a terminal server that can have displays exported across dial-up + VPN. I needed a lightweight front end. I looked at both FVWM and TWM and felt that both of them would be too different for Windows users to figure out quickly.
I settled on XFCE.
Lightweight, fast, low overhead, and quite usable.