Three of our favourite Gmail Labs features have graduated and moved on to out-of-the-box Gmail.
Superstars lets you assign different levels of stars to an email, making a killer to-do list based on priority; nested labels creates labels within labels, so you can organise your mail by sub-categories; and if you use a desktop mail client, you can now adjust which labels show up in your client and which don't. The Google Search Box lab has been removed altogether, since there's already a "Search the Web" button in Gmail. All features are available from Gmails' Settings page. Hit the link to read more. [Official Gmail Blog]