This post is older than a year. Consider some information might not be accurate anymore.
My old Dell Latitude Notebook, 150 GB, 2 GB RAM, Intel Celeron, mainly used for writing stuff, needed a face lift. So I searched for a minimal Linux distribution based on apt. I found Bodhi, the Enlightened Linux Distribution. Bodhi is built on top of the latest Ubuntu LTS release featuring the Moksha Desktop.
The 32-bit version performs very well, running with X he uses only 290 MB.
vinh@latitude:~$ free -h
total used free shared buffers cached
Mem: 1.9G 290M 1.6G 28M 35M 157M
-/+ buffers/cache: 98M 1.8G
Swap: 2.0G 0B 2.0G
Having asciidoctor, python, ruby, git and vim only uses 2.2 GB disk space. The user experience is great so far.