I'm going to give Xubuntu a good try. It apparently runs well in 192MB RAM and well on low-power CPUs. I'm torrenting an ISO as we speak.

I've just installed UNR (Ubuntu Netbook Remix) but after reading the blurb I'm worried about the Intel Atom-specific build optimisations. It's a Pentium III at 866MHz with 384MB RAM. How does the Pentium III handle Atom specific builds of Ubuntu?

It has a Pentium III 866MHz and 384MB RAM.

Yup, I've used full-fat Ubuntu before, so it's a good suggestion. I guess I was hoping someone would say: Yeah, any good Linux distro with blah window manager in X11 build so-and-so

Oh, and the box is un-opened yet, so I don't know the RAM situation. I've got spare DIMMS and SIMMS though so I'm hoping to boost that as much as the BIOS / slots will allow.

Yeah, although the box comes with Win2K I'm likely to bin it and go with Linux. Thanks though.