Following up what Gargoyle mentioned, beware of menus in the front that are in 3 or 4 languages. (IMO) Keep walking. If the menu has pictures of the food........run.

McDonalds comes in very handy for "you know what" stops, and the expresso is very good for €1 or less.

I'll also vouch for the walking tours mentioned by LosAngeleno, (The evening walk through Oltrarno was a nice one also), and a trip to Siena and probably Lucca. Pisa is a ½ day trip.

Take the #7 bus to the top at Fiesole to watch a spectacular sunset.

To get a quick survey of the town, and where you might want to return to and walk thru, ride the little electric A, B, C, and D busses thru the city. (Maps at the ATAF web site http://www.ataf.net)