Quote Originally Posted by cheesecake42 View Post
really? what's the difference? if i'm using fvwm crystal, that what am I using for my desktop environment?
You can look here for info on most of the DEs and WMs out there:

Window Managers for X

DEs generally come with their own file manager, terminal, and other various apps to make a complete environment, whereas WMs only handle window management and you have to add all the goodies separately.