What region or city or area of Italy are you visiting? Regional guides can be more in-depth and have more restaurant and hotel reviews than ones for the whole of Italy.
I can suggest several for Sicily and the Veneto, where I live and have lived. For the other areas I basically defer to other experts. But If I need a guide I use the Italian Touring Club of Italy.
http://www.touringclub.it/ They are the best in my book (no pun intended).
I use the Italian versions normally but they also have them translated into English. Blue guides are nice also.
FWIW the Rick Steves Guidebook is the best selling for Italy, though I have never used them or read myself.
Ciao,
FH