There are to many great choices. Remember, Tuscany is not large.
I think it is great to look for a short-term home, but what do you want in this place?
almost anywhere south or West of Florence gives you immense opportunities to visit interesting places, and the driving is generally easy, away from Florence.
Siena - has probably the most art, architecture, history to offer of the Tuscan towns outside of Florence. Good central location, and you would feel fine if you just stay there most of four days without going on the road very often.
OR: Val d'Orcia...perhaps Pienza or Chiusi...this is the area of the most breathtaking scenery and photo-ops. Many nice small towns close by.
OR: Chianti, perhaps Castellina or the smaller, less touristed (less shopping) Greve in Chianti. But from Greve you could easily drive to Siena for a day, in fact you would want to do that. That drive is perhaps 60 minutes. Chianti also offers fabulous scenery, but it is considerably more hilly than Val d'Orcia, so it is a different kind of scenery.
And anywhere you go in Tuscany, there will be many fabulous wineries within a short drive. That part hardly requires any planning unless you have some particular type or brand of wine to pursue.
indeed, you have a world of wonderful choices. Get into some guide books. you can hardly go wrong.
Edited: 3:09 pm, December 05, 2012