I think it's a good idea to go for SCBCD 5. I've been playing around with EJB 3 for a while and I must say it's less complicated than EJB 2.x. Unless you're dealing with a lot of legacy apps, then SCBCD 5 should be the one
you should pursue. I also heard that there will be a lot upgrade exams coming up for
Java EE 5, e.g. SCWCD (not yet), SCBCD (already there), SCDJWS (not yet),
SCEA (beta). It's always good to keep your skills updated to the latest technologies. My 2 cents
For the book, mainly JPA, I can recommend Pro EJB 3 Java Persistence API by Apress. It's a quite easy to understand and it covers a lot of stuff.