I took and passed the SCJP exam last summer when it was about Java 1.4. I studied using "Sun Certified Programmer & Developer for Java 2" by Kathy Sierra and Bert Bates. My question for the authors is: Is your book designed to specifically help those who might want to upgrade to Java 5 or 6 certification?
There is not that much difference between java 5.0 and java 6.0, so if you are not going anywhere you may go for java 5.0, but will strongly recomend java 6.0