I'm thinking a Lumina 900 would throw very nicely.
its thin, its smooth, Its very heavy for its size, and you wont be able to update the software. its perfect for "bricking" and tossing.
The iphone is so fragile, it will shatter as it leaves your hand, never mind when it lands.
a Galaxy S3 is too light, the wind will blow it into the apple sponsership boards. That is, if apple does not prevent people from throwing rectagular phones if its not an iphone.
Any non-rectangular phones you can think of?