lonely planet and lets' go have the best mix of cheap dining and hotels/hostels and well written recommendations (I'm especially fond of lets'go). in second place I'd get rough guides. One of these should be definite gets on any trip.
DK books and insight guides (published by discovery) and knopf are great for their pictures and thus give a good snapshot of what you'll see.
frommer's and fodors are the big company books and have hotels/restaurants that are markedly more expensive than what young under 30 people would consider. both are worth skipping for the aforementioned. still, go to their websites and copy their nuggets.
rick steve's is too general and seltively opinionated...but has nuggets. it's worth copying down at a book store rick's recommendations for hotels and restaurants.....still, all in all, a good tier down from the other books overall.
<------Has dozens upon dozens of travel guides of all flavors on the bookshelf.