Aside from a college trip to Mexico, I've never been out of the country, but international travel is something that I aspire to and I take a strange pleasure in reading about cities I've never been to, looking through street maps, and reading about hotels and restaurants and odd little neighborhoods. One city I could see myself exploring is Barcelona, so I got myself a used copy of The Rough Guide to Barcelona by Jules Brown (2009). I ordered it off Amazon and actually ended up with a UK version of the book that was withdrawn from a library in Edinburgh -- I'm not sure what it means when your travel guide has actually done more travel than you have.
Barcelona has several qualities that are important to me: It is on a coast; it has an interesting and long history; I can speak one of the languages (Spanish, not Catalan); cool architecture; good food. If I were to go, I think I'd like to spend three or four days in the city just wandering around and people watching and then do some side trips to cool things in the region.
Some things I would definitely want to see and do:
1. The Sagrada Familia and other Gaudí creations
2. Montjuïc (and I would naturally want to ride the funicular up there.)
3. Cable car across the harbor.
4. Old streets.
5. Beach stuff.
6. Exciting and big food markets.
And for some out of town excursions:
3. The Dalí museum in Figures
The Rough Guide series is a solid one, and although I haven't used this guide in the field, it seems to have plenty of useful information and easy to understand maps. Not a lot of pictures, but Google Image Search makes up for that.