Also, if you are a fan of the show's music, start saving up a good chunk of change for around that time too.
Are you implying you know something about a soundtrack release? That would be so cool..
I have the first three sets and I have no interest in getting the fourth (mostly good stories, but absolutely hideous animation redesigns).
They're not all bad. The new Penguin is a vast improvement. Harley is virtually unchanged. And the new Barbara/Batgirl is gorgeous (and Tara Strong's voice is much sexier than Melissa Gilbert's was).