My lady friend (who owns three bikes already) of many years has described in great detail the townie/commuter/beater bike she wants to add to the collection. Being the avid ebayer/craigslister I am I have shown her at least a dozen possible bikes. None of them have passed the test. They were all perfectly fine/quality bikes but they didn't do it for her.

It has to fit but she also has to like it. I personally think used and local is the way to go here so she can ride a few different choices, get quality used components instead of iffy new ones, and so you don't both end up stuck with a mailorder bike that isn't quite right somehow.