Blue Guide and the Eyewitness Guide made a nice pair of guidebooks, the former being more high-brow and the later more pop-y. Palladio's Rome was a gift which, I must admit, I haven't cracked yet--though now I'm back I'm looking forward to. City Walks Rome is not actually a book but rather a deck of handy cards, each featuring a walk.
Now, having also planned trips--and therefore bought books about--Paris and London within the past five years or so, I must say that in comparison to those other two European capitols Rome seems to be rather under-published. For instance, there is no current restaurant guide to Rome that I could find. Travel publishers, take note.
Il Grande Libro de Colori and the blue address book are from the Galley Borghese bookshop. The Geometry of Pasta and Madeline and the Cats of Rome are from this charming English-language bookstore--