You might want to first decide what interests you the most in Tuscany - (the history, the food, the scenery) and then decide what part of Tuscany. From there you can narrow it down to a hotel, a B&B or even a self catering holiday apartment.
Every area of Tuscany is amazing - with so much to offer. Have a look at these links to get a better idea of the areas. Actually any location will give a bit of everything, but each has its own personality
Florence and area (museums...but of course... however also good wine, cultural events and scenery)
Chianti - (wine is key, with easy access to many major cities...and the scenery - including hiking, biking etc.)
Siena and Val d'Orcia - both are a bit south, but they offer a wide range of activities ranging from food to culture to scenery.
Don't forget to look at Maremma and Arezzo - both a bit off the tourist path and very valid alternatives. For example, these two areas would be some of my favorite ... these and Val d'Orcia.