Well, considering I live in Indonesia, I'd say BlackBerry. Everyone uses it. EVERYONE. The messenger is very convenient, even though normal messaging is hardly $0.02, it pays off as time goes, I guess
But whilst living in the States, the Iphone was overly convenient, especially when it comes to researching material for my exams, a lot of apps out there are for studying. And a lot of people use smart phones for very, very dumb reasons, which I find very... Dumb
seeing as you HAVE to get a data plan with the Iphone, i definitly don't want one. I never use the internet on my phone anyway. My dad has a blackberry and its garbage, it has too many features and when my dad couldn't figure it out i found that i too had trouble using it. And as for the android... it actually seems decent but the screens always break.
My pick: cheapest phone with full keyboard+ plastic screen.
All i need in a phone is a full keyboard (i like buttons, not touch screen) and a screen of anything stronger than glass, i skateboard and glass doesn't fair well in my pockets.