I've been playing around with LXDE on the n810 and it's a pretty nice little environment- I think it's a bit lighter than xfce, but looks much more polished and featureful. It doesn't seem quite as quick as Icewm, but it's pretty close and does much more. Everything looks very slick and polished, not 'hacked together' like a lot of the lighter desktop environments. I think it's definitely worth checking out.

I do have a quick question though for the lxde users here: where can we stick a script to run stuff on startup (xmodmap, xbindkeys, etc)? I've done a bit of looking around, and supposedly making an autostart.sh in ~/.config/openbox or modifying ~/.config/lxsession/LXDE/autostart should do stuff, but I'm having no luck at all. If no one knows I'll dig some more and/or post somewhere lxde-specific, but I figured one of us who's been playing with it might have come across something already.
Thanks much.