and FYI i don't use LXDE. i don't know where you got that from... i don't use a DM (kdm/GDM/slim) as i prefer to start my machine and be greeted by the commandline (init 3 essentially). then startx with every component that i plan to use listed. i use compiz-bzr as WM. My desktop 'leans' towards Gnome, but doesn't actually use big parts of the Gnome Desktop (no GS, obviously) no network manager, no gnome-panel, no pulseaudio, etc.
I did try to have a lite KDE desktop, at one point - but doing what i am doing now - works much better, and is less-resource heavy.