I read all of them, and inevitably find something useful in each one. I get most of my information online when planning a trip though. It is amazing how stale, inaccurate and herd like most of the books are. I consider Fodors and Frommers to be the worst; look at one of the books in a particular series from 10 years ago and you will likely have them recommending the same places to eat today...b.s.

I like the Rick Steves books for some of the tips and tricks that he puts in that the other books leave out. I think ignoring him on principal is fine for some, but if your library carries his (or any) books give them a read.

If you can find one or two good tips from each book and access the books at a local library, I'd say you're doing great.

Another option is to use the free podcasts in iTunes to do some planning. I use these extensively to kind of re-enforce what I think I know or to fill in the gaps. They are easy to listen to and there are a ton on Italy.

Ciao.