Capitol Hill Books has always been a great place to while away an afternoon. And with the 10 percent-off card for frequent buyers, the 3,000-square-foot bookstore is habit-forming. The new travel section is just making matters worse. Because it's stocked with 4,000 travel guides, armchair travel books, memoirs, dictionaries, language books and books in other languages, there's no better place to see the world. Check the shelves regularly, because books on Thailand, Cuba, Vietnam and South America disappear quickly. But at just $5 to $6 a pop, it's suddenly affordable to go places.