I will be in Florence with my husband and parents for four days. We will not have a car. What are our best possibilities for a day trip---one that is not more than an hour and a half away, perhaps, and where the bus/train puts you in a decent position to see the town on foot?

Lucca, Pisa and Siena are good daytrips from Florence, within 90 minutes away. If you choose Siena, I would take the bus as it brings you closer to the center than the train.

Another vote for Siena; lots to see, and an easy bus ride from Florence. Take the "express bus" if you can, I think it takes right at 90 minutes.

Another possibility is San Gimignano.

There are many small Tuscan towns that are wonderful to walk around, also. They have city buses that take you to them. Greve is one, but you can go anywhere with in an hour on a bus. Fiesole is not to be missed. After you are let off in the piazza, walk up to the Franciscan Monastary, then come down and walk around the Etruscan ruins museum. There are incredible views of Tuscany all over.

Go over to the transit station behind the main train station (near Santa Maria Novella) and get the bus to Siena. A great day trip.

Without question, San Gimignano-an ancient Etruscan city-it's like a town from a fairy tale, so beautiful to walk around in, the local specialities, grappas, cheeses-are fabulous. Wine tastings are available at a number of restaurants, just walk the cobblestoned streets and look for the signs-some of the restaurants have lovely views of the Tuscan countryside. Spent an idyllic afternoon there sampling several wines, with bruschetta, and local cheeses. Then Lucca.

Pisa is a dump. I suggest siena as others have. but above that, i would choose to spend time in the Chianti region which you can get to easily as well.

San Gimignano, Hands down. Siena second. I have visited these as well as Lucca, and Pisa. Siena is much bigger than San Gimignano, and so has a feel a bit more like Florence. San Gimignano is a small town with different architecture, and an incredible view. A Florence resident suggested it to us and was right. The bus will take you there and drop you right at the gates of this hilltop town. Do a google search to get a picture of the town.

Pisa is very popular, but touristy. Only you know if you would want that.

Perhaps less than a day trip, but take the bus to Fiesole, walk around the town, enjoy a superb meal with a view overlooking the countryside, and be back to Florence very conveniently.

With but four days in Florence, you would have a lot to see in town, and while the other places mentioned are lovely, you might not have time for a full day away.

Enjoy your trip.