There are a wealth of road maps of Italy available, but this one is my very favourite and has travelled with me in my rucksac, handbag and car for the last ten years and never let me down.
From my very first solo trip to Italy exploring Florence, Pisa, Massa e Carrara, San Gimignano, Volterra, and driving around the Tuscany villages and towns from the wonderful base of the town of Lucca. And then, later, Siena, Monteriggioni, Pienza, Montalcino and Montepulciano, and Pienza... And now my home - la Maremma in Tuscany and Lazio - I have travelled with this map.
It is one of the series of Touring Club Italiano maps that cover the whole of Italy, region by region. And is now very well worn: cellotaped along every fold as a result of daily use, but I won't part with it for a new one! (Not yet anyway.)
If however, you are looking for the whole of Italy in one map with detailed street maps of each of the main cities, then this spiral-bound Michelin Italy Tourist and Motoring Map with cities may be just the thing. Its cartography scale is 1: 300,000 and includes seventy-four town maps.
Although not as convenient to carry around with you whilst exploring on foot, it would be perfect for keeping in the car or planning your next days trip in your apartment or hotel etc after dinner.
Explore some more...