Branding your law firm begins with your domain name because it affects your website and your email adddress. If you are using an email address that terminates in a domain other than your own firm name, or your name personally, you are missing an inexpensive way to brand yourself.
I see a lot of attorneys who use email accounts from Yahoo, AOL, Gmail, and Hotmail, and when you do, you are marketing those companies and not your law firm. Having a domain from someone else like that also sends the wrong signal to your clients about how serious you are about your practice.
I own the domain glenngarnes.com, and my email address is firstname.lastname@example.org Now, if anyone I interact with can’t remember my email address, then I’ve either done a very poor job of marketing myself, or they’ve got serious problems.