I'm thinking of getting an Iphone when I come off contract next month. I've always had Nokia phones before as they are really loud on the ring tones and the loudspeaker. I need a clear and loud phone as I have a slight hearing problem. How does the Iphone compare with Nokias for clarity? Is the loudspeaker nice and clear? How loud are the ring tones? I don't want to get stuck in to a 2 year contract on a phone I can't hear properly.

Also, any other real differences between Nokias and Iphones I should be aware of?

Thanks