Go for the book by Kathy Sierra and Bert Bates for SCJP. But come time for your examination, you might want to consider the 1.6 exam instead of the 1.5 exam. Currently, there are no study guides available for the 1.6 exam and the changes from the 1.5 to 1.6 exam are minimal to which you can simply study the objectives list and plan for study of the differences between the two. See Sun's site for more
information regarding this.