The answer to that question really depends on a) what your interests are and b) how you intend to travel around. Tuscany, like all of Italy, has a good, safe public transport network of regional trains, local and longer-distance buses. As everywhere in Italy (and all EU countries) some places are easier to access by public transport than others. If you want to stay entirely off the beaten track for e.g. hiking in the countryside and/or visiting vineyards you'll need a car. If you don't, you won't. If you're interested in seeing all the major tourist sites and sights you should visit Florence and Pisa' If you're primarily interested in art and/or sculpture, you should visit Florence for its fantastic museums. If you're primarily interested in Medieval architecture you should visit Florence, Lucca, San Gimignano, Volterra and Siena. If you're primarily interested in Etruscan and Roman remains you should visit Fiesole, Volterra, Vetulonia, Cortona and Chiusi. If you're primarily interested in wine-tasting you should visit the areas surrounding Chianti, Montepulciano and Montalcino. If you're primarily interested in hiking and exploring the landscape you should visit national parks such as the Apuan Alps, the Parco Nazionale delle Foreste Casentinesi, Monte Falterona e Campigna and the Parco Nazionale Dell'Appennino Tosco-Emiliano. If you're primarily interested in good food and good wine you should visit anywhere in Tuscany. If you keep well away from eateries on the main tourist routes and near major tourist sites you're pretty much guaranteed to get good food & wine and not get ripped off! So....what are you primarily interested in seeing and/or doing?