Well, E can load previews of tons of background-images and that makes E huge in memory consumption, but you don't have to let E do that. And if you don't, E uses about the same amount of memory as Sawfish. I never could get the hang of it. I have been using E with gnome for a long time, and loved it. Currently I use IceWM with gnome and love it too.
Ice is fast and small.
I found a theme for it which is quite acceptable. There are some quirks with the floating toolbar of DDD for instance, but so far nothing I can't live with. I also use KDE2 sometimes but it's a bit slow, big, buggy still for our tastes. You just have to change the focus mode to click and select an option that says something like raise focused window. There is or was an option that was something like click-through mode which one would most like to want to toggle too, that way one does not have to click twice on unfocused windows to get something to work.