Staying in Florence for a week. Is it worth hiring a driver for a day to see more of Tuscany? Does anyone know of a reasonable and good driver?

Of course it's worth it need one ask. However you should think a little about where you want to go and what kind of things your interested in seeing so you can get the best possible advice from the other great fodorites.

There's only so much you can see in one day as you have implied. You need to know where to go and what you really want to see IMO.

For one example, you could easily spend a day seeing only Siena and you wouldn't even need a driver to do it.

If you pay my airfare, I'll be there. I'll rent a car and take you wherever you want to go whenever you want to go, except the centre of Florence.
despite my offer I'd take the bus to Siena, and spend the night there,return to Florence in the a.m. You'll see the countryside and get to enjoy Siena

Have visited Siena and loved it. But am looking for a different experience. Perhaps it is better to do a few day trips. Prefer to use public transportation as private drivers are over the top expensive.

If you have a week I'd suggest a overnight in Tuscany? I really like San Gimignano, we rented a car an drove

You can reach some places easily by train and others by bus. This map shows some of the bus connections from Florence, but there are others such as Lazzi that goes to Lucca and several other bus lines. The tourist office will have info.

http://www.sienamobilita.it/mappe/Mappa_EXT.pdf

There are lots of tour companies with day trips if you don't want to hire a driver. The tourist board will have a list of those also. CAF is one of the cheaper ones.

http://www.caftours.com/excursions-and-day-trips.html

Thanks. What were everyone's favorite towns in Tuscany?

Do you mean favorite towns that can be visited in a day trip using a driver? Using public transportation? Or joining a tour?

Tuscany is 9000 square miles, so "favorite" does not always translate to "accessible."

If you decide to hire a driver to do Tuscany for maybe a single day, Luca at hillsandroads.com is a favorite of many here, including me.