I positively love it!
Its really changed the way I communicate. The best things for me are:
1. It uses Microsoft Outlook. I have all my contacts, calender and email accounts synced. I can access my email anytime through out the day when I am traveling. In the past I had to wait until I went to my room and checked mail via my laptop.
2. I had an iPod but I couldnt be bothered carrying it around. So basically all my music stayed at home. Now when I am bored I can listen to all my favorite stuff. iPhone synced up with my existing iTunes and downloaded all my stuff automatically.
3. I love the browser and actually do use it quite a bit. I never ever went online with my Razr so this is a big jump for me.
4. I can actually send text messages. I know this sounds like a small thing, but I didnt have a Blackberry before so texting was so tedious I never did it. I find the iPhone easy to use and am a textaholic now.
Is iPhone perfect? No, but its so damned close Im satisfied.
The only thing I really miss on this phone is my Ringtones. Apple will be releasing a patch soon so that you can sample your own ringtones from your iTunes collection. Once thats ready I will say iPhone is perfect (for my needs anyway).