Favorite Tuscan towns and villages?

Montepulciano is a great place to visit. So is Pienza, you should take that in as well, then on down to Orvieto in Umbria before hitting Rome.

Orvieto. Not Tuscany, but close.

Arezzo is very nice as well. Perhaps a bit larger than what you are looking for, but many interesting sights and some great restaurants (follow your nose).

See today's USA Today travel section for a Rick Steves listing of great smaller Tuscan towns. He goes over them one by one.

I like Volterra and San Gimignano. And Orvieto (in Umbria) is another favorite hill town.

While driving south from CT, stop in Lucca and Pisa, 2 important stops will be done.
Monterigionni is worth the hour to spend there. It's so small, yet so gorgeous.
And as some others mentionned, Pienza, Montepulciano are great.
If you have time, Montalcino and close, the Sant'antimo abbey would be great additions.
While going south to Rome, Orvieto as others mentionned as well.
If you have more time, Cortona and Arezzo.

There are so many charming towns in all of Tuscany. You may just happen upon one while you're driving and want to stop in.

BUT, I would not discount Montepulciano. We are taking our two teens there next month (we will also visit a winery or two in Montalcino.) The warmth that exudes from Montepulciano (not just the heat!) and the relaxed vibe really makes this a great town to visit for anyone. Last time we were there we hiked up the bell tower and were rewarded with an amazing view of the countryside. My teens liked climbing up the different towers in Paris and London so I'm sure this is something they'll love to do. Then you can grab a gelato and walk around. If you do want to taste wine, but don't want to visit a winery, there is a great wine shop on the main road in town. I forget the name now but they are so kind.
Whatever you choose to do, I'm sure it will be wonderful. Enjoy your trip!

Yes, I do plan to go to Orvieto, Originally, I thought we would drive back up to Florence to catch the express train to Rome, but then I realized if you are as far south as Montepulciano, the drive to Orvieto is about the same amount of time as to Florence and then the train trip is also the same amount of time as the express from Florence. So figured we would drop off our car in Orvieto.

We do plan to stop in Pisa before heading further south towards Volterra and San Gimignano. Not sure abut Lucca. I don't want to try and cram too many things into a day.

One thing I am not certain of - whether to pick up the rental car in La Spezia and drive to Pisa, or just take the train to Pisa and pick up the car there. I assume we would save some money by picking it up in La Spezia since we would not be paying for train tickets all the way to Pisa. But maybe it is more convenient to take the train to Pisa?

Montepulciano is wonderful. We also enjoy Pienza and Montalcino. On our first trip to Tuscany, our first hilltop town we visited was Radicofani. I was astounded at how charming it was. Nearby Celle Sul Rigo and San Casciano Dei Bagni are also lovely and well worth a visit if you are nearby. No blockbuster sites in any of these last three, just picturesque and typical Tuscan villages.

I'll echo Montepulciano, Pienza (fabulous) and Orvietio in Umbria. Cetona is a very pretty little village, as is the unusually designed Lucignano. I liked Casole d'Elsa and San Quirico, and I'm one of the few who will trumpet Chianciano: the modern main drag is quite interesting in terms of shopping, the small, old core is charming, and there is a fantastic view from the balcony of a mom and pop cafe not far from a convent (that's the best I can offer).
The Abbey of Monte Oliveto Maggiore is in stunning surroundings, and has a decent cafe.

Definitely visit Montepulciano. While there go to Cantina de' Ricci and do a wine tasting. Also go to the top of the bell tower for some amazing views. I enjoyed Montepulciano more than Pienza probably because it was much less crowded. The tour buses have fairly easy access to Pienza while there really isn’t any way for a tour bus to get large groups into Montepulciano.

If possible make reservations to have lunch at Podere Il Casale. It’s a wonderful organic cheese farm. The view from their terrace is wonderful and the food was exceptional. The owner is from Switzerland and he is a fascinating. If you want you can have a tour of the farm.

Keep in mind that depending on the age of your teens, they may be of age to drink in Italy (18, I think, though a couple of websites say the age is 16 for drinking beer/wine - ask when you're there).

We love the town of San Gimignano, and have stayed there, in the town, several times - it is much more wonderful in the evening, when the day-trip visitors have left, and quite peaceful to sit at a cafe on the main piazza and people-watch. Near there, if you want to do something a little different, you can take a short hike to an abandoned castle, Castelvecchio. It's about 5km south of town, west of the small burg of San Donato; the hotel we were staying at gave us directions. Google for more info.

Monteriggioni is pretty, and nice for lunch. Certaldo has some interesting sights. In Volterra, don't miss the Roman theater on the north side of town. Orvieto is also a good place to spend a couple of hours, especially if you're planning to drop your car there.