OpenBSD's cwm for FreeBSD
cwm's advantages stem from the fact that I am a keyboard jockey with very little desire to use a pointing device.
cwm has great keyboard control for manipulating windows and launching applications, but still allows for the free-floating feel when I use an application that is more pointer-oriented (Firefox or rdesktop to Windows box).
Also, I like using my screen real estate for terminal windows and applications, not widgets or title bars, etc...
Tiled window managers are cool too, but a little more awkward for me as a user.
BTW, evilwm is in the ports tree, and it works -- but there is no application launcher and the granularity of window movement was too course. I started digging through evilwm's code to add the features I wanted, but found the design of OpenBSD's cwm and it's source code to be easier to work with -- and it already had the features I wanted.
I did like evilwm's "jump-to-corner" keyboard shortcut functionality to be pretty convenient, so I implemented that feature.
Have fun.