Boards and Wards is awesome. I didn't get it till my last rotation of 3rd year and wish I'd had it all year. Plus I saw a lot of interns using it to review for step 3 as well.
This one has great charts and bullet lists for quick reviews while waiting for the elevator, waiting for the attending to come for rounds, etc. It fits easily into a white coat pocket, although you won't have much room left for anything else. At 350+ pages its a little heavy, but you can balance it out with a Pre-Test or the Washington Manual on the other side.🙂