Email is great but most non smart phones dont handle email all that well. Additionally in order to send a quick photo to all you friends ho have smart phones, I would need to have their phone numbers and email information which isnt a big deal but MMS is standard way sending pictures when it comes to phones, so why wouldnt an advanced phone support this standard. And what i dont get is how can ATT say they are concerned about increased data traffic from MMS when every other non iphone can send picture messages.
But you can email to the phone number, and they can reply to your email via SMS or MMS. All of my contacts do this, from Verizon to Sprint. It's no big deal, I use email all the time to the phone number. I do pay for 200 SMS a month, just in case people screw it up and text me, but since I've had the phone so long I'm debating whether it's worth it or not anymore.
To give you an example, I email my wife's phone one of two ways:
email@example.com or firstname.lastname@example.org
These are stored in my phone as mobile numbers, and when I start typing the contact into the email field, it pulls up the list, I pick which email to send to, and send. Not that tough, I have push through mobile me and everything works fine, despite AT&T.
She just replies, or enters an email address into her phone and sends it. This has been working since I had a Palm Treo 650. It worked on my Windows6 phone as well, although those phones sucked, even on Verizon (who I left for the iPhone.)