My family has had Andriods, Blackberries and Ihpones. We are all beginning to migrate towards Iphones now. Although there is a rumor around here that Andriods are best, I prefer Iphone. We never had good luck with blackberries. But, I also know people whom love blackberries.
It all boils down to personal preference. With the apps you can get for a andriod/IPhone, you can virtually call for free. I am not sure if Blackberry allows skype, but Iphones do.
With this kind of thing, i always recommend you go with what you want, cause if you don't like the phone your stuck with it for 2 years.
I am not by any means a Expert, But Have dealt with, both Iphones and Blackberries.
So, In my opinion : IPhone I Choose You.