I don’t know how many times I have seen law firms and solo lawyers with e-mail addresses using provider domains like AOL, Comcast, Earthlink, or Verizon. Years ago it was quite impressive if you had an e-mail address at your own domain; clients and potential clients saw that you were serious about an Internet presence. Now, having such an address is much more of a necessity, and attorneys who do not have one, should get one as soon as possible.
These days, there are so many Internet providers that will allow you to have multiple e-mail addresses at a custom domain that there really is no excuse not to have one. If you already have a web site, then it is easy. Most all hosting companies offer multiple e-mail boxes in your domain as part of their services. Just contact them and have it set up. If you do not have a web site yet, you can still register a domain, “park” it with a provider, and just have e-mail until the site is set up. 1and1 Internet, for example, offers a $1/month package that gives you six e-mail accounts, 2 Gb of mailbox space, virus and spam filtering, and web mail access (for when you are on the road). Domain registration is $5.99/year. Other providers, like GoDaddy and Yahoo, provide similar packages. These providers can also often configure auto-responders for each address that can be used to send a response when you are out of the office or on vacation. Having an e-mail address at your own domain also allows you to change providers without changing your e-mail address, so you can always take advantage of the best deal.
With all of this, there is really no reason not to jettison that email@example.com address and get JohnDoe@DoeLaw.com. The web site should follow, but you should at least have the custom address. These days, it is almost expected.