For me, I'm sun certified
java programmer 1.4, I wanted to take the 1.5 exam as a way to tam the new features, but I work as a full time Java programmer, so I couldn't wait that long, a lot of books covered the new areas, and I'm using the new features in a daily basis, so I quit thinking about the exam, I participated in many other exams, and I may think about the 1.6 exam when it's released (only if there is available book at time).