I always use an email signature block. The content is dependent upon which email account (I use many), and to whom I am sending the email. My stock signature is:
L1: Apple Logo and First/Last name
L2: Email address. I realize that this is redundant but it's a throwback to my work email where it's required.
L3: Contact information, usually a Phone Number and/or Street Address. This line often gets deleted before the email is sent, depending on who/why/need to know
L4: Twitter handle. Again, can be deleted before hitting "send", as the situation warrants.
____________________________
My Name
email:
me@mydomain.com
phone: 800.555.1212
twitter: @mytwitter