I like running Linux Mint LXDE edition on my Atom/ION machine with a 1G of memory. It's based on Ubuntu (I think the latest version is based on 11.04), but uses

I like running Linux Mint LXDE edition on my Atom/ION machine with a 1G of memory. It's based on Ubuntu (I think the latest version is based on 11.04), but uses LXDE, which is the lightest "full" UI that I could find. I put Chrome on it and it works fairly well - not exactly snappy, but sufficient for Web browsing. The plus side is that all the software that's in Ubuntu is still available (from the repositories), which might not be the case with some other minimalistic distros.