You can also include links to online portfolios, if appropriate, or a link to your professional social media account such as LinkedIn or Twitter. You don't want to make this section too cluttered, however, so restrict yourself to the most relevant information. Here's how to set up an email signature, along with more advice on what to include in it and what to leave off.
Remember, you're hoping the person who receives your letter has no memory of your closing at all. The last thing you want is a hiring manager going into an HR meeting with your cover letter in hand, asking the team if they want to meet with "Mr. Kindest Personal Regards."