I'm unable to send a picture to a friend via MMS (like I was able to on my SLVR for the past two years), and according to posters at the AT&T user forums, I cannot unless I pay more for a Blackberry data plan? I have the unlimited MMS plan, but if I'm going to have to pay more just to send an occasional picture to someone, I'll have to rethink my purchase.

You need service books to send MMS if I remember right, so, yes, you need a data plan to get the service books to send MMS.