My prepaid flat-rate plan includes "unlimited" SMS/MMS (and don't get me started on use of the word "unlimited" by service providers...). In any case, it doesn't cost me anything extra, and it's way easier to be able to accept and send MMS messages to people in your life who are going to use that channel of communication with you regardless of how many times you tell them to use e-mail to talk to you THAN it is to face them after they've sent you something and then you run into them a few days later and they want to know why you never responded. (EDIT: ...okay, that was a terrible run-on sentence.)