We've already upgraded most of our clients to 6.20, but if we haven't done you yet, please let us know. There are no security updates in 6.20; this is mostly a housekeeping thing.
In addition, Drupal 7.0 has officially launched. Pretty exciting stuff! But, much like the 5.x to 6.x transition, not all the functionality you find in 6.x has found its way into 7.0 yet. We'll be deploying upgrades to 7.0 probably later in the year, or early next year, but only when we can do it smoothly and without losing any vital functionality.