If it is just for fun or nothing important, iPhone is good but if it's for business, I'd prefer android of any brand or model. I think android phones have the most useful features for business transactions. Though I haven't checked the latest iPhone in the market, I'm not sure if it has the necessary features needed for work or business.
I am using Nokia 5800 EM currently and I love it...though I am planning of getting some low profile Nokia phone after this...I'm done with smartphones
There's no the most in my point of view, but BlackBerry smartphone is quiet amazing mobile phone ever
Got an iPhone 4 right now and couldn't be happier. Previously was a blackberry man. My last two phones were the bold 9700 and the torch 9800 and I swore I'd never get an iPhone, but now I have, I love it.
I like all N series... That is so cool and attractive as well. But I am using Motorola v3i right now.