This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
I would take scjp6 and then take scjp7 exam(s). Reason: a lot of companies will use older jdk versions than 7, so having both will be more valuable to them than only passing scjp7. That's why I have scjp for jdk 1.4, 5.0 and 6.0 myself