There's nothing quite like the iPhone.
I'm typing this from my HTC Desire, which people will say is a good challenger to iPhone, but is still very clumsy in my opinion.
I've spent a good 10 minutes trying to write this post, which would have taken 1 minute on an iphone.
It's difficult editing already typed text, the keyboard is more narrow, even if you can revert it to older style keyboards, and the browser has a cheap, jumpy feel to it.
The internal storage of HTC phones is rubbish, which does matter and there's not enough decent apps, contrary to what people say.
There are no decent alternatives in my opinion. I would buy a cheap iPod Touch and a cheap phone with a good battery life.