In what is probably the most most confusing release announcement I've read yet, a new release of Drupal has been made available. I believe it's 7.7 that's out, but 7.5 and 7.6 are also mentioned so it's a bit confusing. See for yourself:
As you can see, it's either 7.5 or 7.7 or maybe 7.6?
Long story short, if you run Drupal 7.x, you should probably upgrade. Hopefully, we'll see more clarity in future release announcements.
Here's the full announcement (note the URL is 7.6 but the announcement says 7.7): http://drupal.org/drupal-7.6