I was in Tuscany last year - absolutely fabulous. Flew into Pisa, train to Florence, a few days there, then hired a car and stayed in a villa in the countryside. Depending on where you are if you can, hire a car and definitely get to see Siena, Lucca, Volterra, and San Gimignano is one of the best preserved medieval towns in Tuscany.
The only disappointment for me was Pisa - apart from the leaning tower, there wasn't much else to see - it was also the most expensive area in Tuscany.
Depending on when you go, there are often interesting festivals in towns and if you are into opera, the Puccini festival is worth checking-out.
Enjoy