The following link will take you to Steves-Digicams, where there is a section on "the best cameras" by category. Does your girlfriend want a very small, compact camera? Does she want a lot of zoom? Always look for optical zoom, not digital zoom. Will she be taking photos in low light conditions? Look for cameras that do well in high iso modes.
For your price range a dSLR is out of the question. But there are very good compact cameras with a lot of features that will probably be just fine. Good luck!