The Vin Santo is a traditional tuscan sweet wine. It is made with white grape varieties and, when producted with the ancient method, it is really good and wonderful to be drunk with tuscan dried dessert (Cantucci, Cavallucci, Ricciarelli, Panforte, Pan co’ Santi ..)
The problem is, that it is very difficult to find a good industrial Vin Santo. The traditional procedure is so long and so expensive.. For this reason my suggestion is only one: to come to Tuscany and to pray to find someone that let you taste a homemade one or to look for a DOP wine. It is only since 2007, that the method has been registered and now only wines mades following the ancient procedure can be called Vin Santo (but pay attention to “Vino Santo” or other similar names!!)
In any case, my suggestion is to try between the most expensive (don’t believe that a Vin Santo can cost less then 19/20 euro per bottle).
I have bought so many times Vin Santo, but it was really fantastic only twice: first time, it was when an old friend let us taste his own; the second one, it was my father-in-law to bring it : he bought it in Consorzio Agrario in San Quirico d’Orcia, but then, the time afterwords, he brought another bottle of the same Vin Santo and of the same farm and it was no more so exceptional..
For knowing more about Vin Santo (Montalcino Wine Blog)
For more information about Vin Santo (Wikipedia)