This is a similar thing which got me to drop to a custom setup. Okular triggering X to get the OOM kill in the middle of a presentation was unacceptable. Sure, the machine had 512MB of RAM, but it's what I had.
I got that machine booted on a stripped down Fedora (still the default kernel) with ~60MB of RAM used. 80MB after starting X. It also rebooted in 45 seconds (Internet to Internet...manual login and ifup) with Fedora 13 or so. My F15 machines boot with around 200MB used, though Rawhide has it back down to the low 100MB range.
At work, I have a system in a VM that needs quite a bit of memory (relatively; 6GB has usually enough, but my machines have only 8GB), so stuffing my system in beside it for some development (though not too many builds) pretty much rules out the DEs as usable.