Thanks for the tips piknik and Maineartist !
Rough guides, I still haven't tried, but the LP is sorta my bible to plan and budget (with the french guides "Routard", which I highly recommend btw). And for a tight pocket like mine who wants to travel as long as possible, I spend a lot of times on the prep part of a trip. Especially a long one/RTW.
I'm personally not crazy though about the "best cities" type of guide because they go for the obvious. I'd like someday to do a round the world trip of the 20 less visited countries and write a guide book !
A good book to find ideas and infos to work while travelling is "Work yourself around the World" by Susan Griffith.