exmap is great. I'm impressed that my whole desktop only uses 288MiB of memory out of 512MiB on my ppc. I guess that the rest is kernel buffers/caches. Yes that's the real memory usage of my GNOME desktop : 288MiB

Hum, wait a minute, what about my 500MiB of swap ... What matters is overall memory usage including swap. Not only resident memory...