I went on a Reinaldo Arenas binge and bought The Doorman, Old Rosa and Hallucinations; his books show up relatively rarely in used or new bookstores, so when I see 'em, I grab 'em. I'm still missing volumes 3 and 5 of his Pentagonia series; they're just really hard to find.
I got Old Rosa at the Strand in New York and the other two at Raven Used Books in Harvard Square. I love those stores!
I got London Under by Peter Ackroyd from work; it's a history of the underground of London, not just the public transportation system but all the stuff under the sidewalks of the city. I thought it would be fun to read to prepare for my trip.
I picked up The Book and The Brotherhood by Iris Murdoch at one of my favorite used bookstores, the Montague Book Mill. Because you can never have too much Iris Murdoch in your life.