The Rough Guide is the way to go for touring and paying fair prices for what you get. Make sure to buy the most recent year and you'll be good to go. (and reserve way ahead of time in Italy especially in Venice, Florence!) The hotel and restaurant recommendations are reliable. The sometimes not-so-politically correct histories within are amusing enough to read the book cover-to-cover. Plus if a place is lousy they tell you not to waste your time instead of sending you there as a plug to sell the guide. Other guides sing praises about places you go to that are trash heaps filled with other tourists that have apparently read the same misinformed guide! Yes because it is a guide and reality changes faster than print: very, very rarely you will find something out-of-date or be disappointed by a recommendation. But less so with Rough Guides.
I've tried them all. The competition is not worth considering as they are almost always outdated or so limited to one set itinerary. Frommer's = way too expensive for what you get : hotels, restaurants for rich American tourists. Let's Go = hohum, many establishments do not still exist and if they do you'll be disappointed! (Best pizza in Parma = inedible) Lonely Planet = inspiring photos but lacking substance. Rick Steve's = ridiculous inaccurate hand-drawn maps and the one proscribed itinerary to visit an entire country.
Go Rough Guide. No regrets.
PS If you are planning on driving in Europe consider taking a GPS unit with you that has European maps and POI (point of interests) in it to alleviate stress and promote family accord. This is especially important when entering foreign cities. Using the GPS you can select a parking garage near the hotel (if none at hotel) before arrival, safely navigate there, park the car, and hoof the rest of the way on foot. Don't make the same mistake I did in Siena!