First of all, you can chose between Belluno county (Veneto region) or Trentino Alto Adige region. I would suggest you the Belluno county, less crowded, cheaper and more Dolomitic.
Belluno and Feltre are the biggest cities, and from there you can walk in the "Parco Nazionale delle Dolomiti Bellunesi". The highest Dolomites are northern, the biggest towns are Cortina (expansive), Pieve di Cadore, and Auronzo.
But then all depends if you prefer towns or villages, you have hundreds of choice, from where and how (car, train, bike) you arrive, which kind of location you look for (hotel, B&B, flats...). And about the hikes, there are paths for all levels and times, it depends on your taste (if you want to walk at 2000 meters or if you prefer under the trees)..
So, do you wish to be more specific?