I know a lot of people hate AT&T but I really can't stand CDMA phones since I travel so much 
I've been on Tmobile with an iPhone ever since they've been unlockable - solely for price conscious reason. Now, with the new AT&T plans I can justify the switch
Current Plan - Unlimited Talk, Text, 4G (which I can't use) - $79.99
New Plan
AT&T 450 minutes - $40
Unlimited Text + Unlimited Mobile to ANY Mobile (best new feature ever!)- $20
Unlimited Data - $30 (the store employee actually hooked me up and did it in store with a 2G iPhone I had)
15% FAN discount
In the end my phone bill dropped $5 after tax and I'm still ahead. I can't recall the last time I called a land line anyways
So - basically unlimted everything except landline calling for $75 after my discount
I can't wait to use the iPhone to its full potential - enough is enough with EDGE. TMobile sucks for not being able to get the iPhone. It's been good - well, it's been ok - but now I'm leaving 
I've been on Tmobile with an iPhone ever since they've been unlockable - solely for price conscious reason. Now, with the new AT&T plans I can justify the switch
Current Plan - Unlimited Talk, Text, 4G (which I can't use) - $79.99
New Plan
AT&T 450 minutes - $40
Unlimited Text + Unlimited Mobile to ANY Mobile (best new feature ever!)- $20
Unlimited Data - $30 (the store employee actually hooked me up and did it in store with a 2G iPhone I had)
15% FAN discount
In the end my phone bill dropped $5 after tax and I'm still ahead. I can't recall the last time I called a land line anyways