I can suggest Zorin OS Lite or SolydX, both of which aimed at older, low powered machines. I would say SolydX is the better option.

Zorin is another ubuntu based distribution and this one has been accused of trying too hard to be like Windows. Version 6.2 is based on the LTS version of ubuntu and latest is version 7. Runs "prettified" LXDE desktop and has a "look changer" to look like various propriety desktops. The lite version is free but there are versions with paid support - forced payment I might add. That won't sit well with some!

SolydX is a rolling distro based on Debian, running LXDE. There's a KDE version SolydXK also. SolydX looks good out of the box, has good hardware detection and doesn't charge a fee!

For Windows XP orphans either will probably keep them happy. There's a large ubuntu and debian user base and community support is readily available. In my experience most people coming from XP don't care about Linux for what it is, they just want their computer to look good, work fast and do what they want it to.

Rgds,

Martin