3215 Panicale and Paciano

These are two "walled towns" to the south of Lake Trasimeno, both are very well preserved, and the only entrances are by seriously fortified gates.
Panicale has more to offer in the way of art - with a stupendous Il Perugino fresco (just outside the walls), other notable works in the duomo, and open air music every Thursday in the piazza. (Sometimes the music isn't what everyone would call art, but it is always good fun!) Panicale has a well staffed tourist information office, with plenty of ideas for visits to neighbouring places of interest.
Both towns have a choice of good restaurants, my favourite in Panicale is "Masolino" - traditional fare nicely presented by friendly staff, and in Paciano "La Logetta" offers a slightly baffling menu (they do not distinguish between antipasti, primi and secondi - you can just mix and match at will). La Logetta has a very interesting choice of dishes to appeal to vegetarians, but plenty of meat as well.
Panicale, in particular, is quite an international community, majoring on American visitors in the summer - (but people who are renting apartments individually rather than large hordes) - so there is always someone to chat too in the Piazza in just about any language.
Pleasant panoramic walks through woods can be reached from either town.