I have switched from Lubuntu to Debian Stable, and my system is stupidly light!
You are not misreading it. It really does say 68.5 MiB! This is Debian Stable, not something like Tiny Core!
I am running Arch Linux on an HP dc5700, with a 3 GHz Pentium D and 1GB RAM. With these low specs, a lightweight distro is necessary, so I am using Arch Linux with Openbox.
The dock at the bottom is wbar, the system monitor at the side is conky, and the panel at the top is fbpanel.
I am using the oxygen-icons icon theme and the green form of the archexagons-wallpapers wallpaper (no longer available in AUR).
My openbox and GTK themes are both gtk-theme-orion.
In order, the dock goes: