Most of those are self-explanatory, but Go To Label and Vacation Dates might be less evident. Go To Label can be used in combination with keyboard shortcuts ("g" and then "l") to place the "label:" operator in the search box. Vacation Dates lets you specify which dates you'll be away in advance, so you won't forget to turn on the vacation responder after you set sail.
In addition to promoting some Labs features, Google will axe several others. Over the next few days five Labs items will stop working and disappear, including Muzzle, Fixed Width Font, Email Addict, Location in Signature, and Random Signature.