fvwm - ancien (artefact, i'd say)
fvwm2 - old (stable. 2.4)
fvwm-crystal modification of fvwm (probably 2.4, i dunno) [looks beautiful by default, AFAIK]
fvwm2-devel - new (unstable, however it's very stable, 2.5)
The only thing i stack is because i love full terminals and dwm because if you don't know key combinations you cannot do completely nothing!
The stupid thing on me is that when i have gui environment, i want something more terminal and when i have terminal, i want something more graphical.
With simple words i don't know what i want P