3 Iphone 4s on At&t = 220 a month bill.
3 Really really nice android on Virgin Mobile = 75 a month bill and it works fine.
Why anyone would go with a contract phone over a prepaid is beyond me unless you just want a free phone that will end up costing you alot more over the course of a year.
And baddog you can absolutely port a prepaid number as well
You can just about do any number now adays.