If you have obtained your very own Facebook username, there is a new feature, announced by Facebook today. Now you can skip typing the extra characters that comprise your email address and instead you can use your shorter username to access your Facebook account.

As per Facebook Blog:

A couple of months ago, we made it easier for people to find and connect with each other by using Facebook usernames. Beginning today, you also will be able to log in to your Facebook account with your username from any Web browser, mobile phone or Facebook Connect-enabled website.

You will still be able to log in with your email address. We just wanted to add a more convenient way to access your Facebook account. A username gives you an easy-to-remember web address for your Facebook profile so your friends can more easily find and connect with you. If you don’t have a Facebook username yet, you can choose one here.

I guess this is the logic thing to do.