I use both a curve and iPhone on a daily basis and I am a little torn over the iPhone2 or the bold. My random iPhone/Blackberry thoughts........
1. It is so hard to go back to the small blackberry screen after using the huge iPhone screen for awhile.
2. I commute two hours a day, so the web browsing on the iPhone comes in really handy. The browser combined with the big screen is awesome.
3. I watch alot of tech videos on the iPhone during my commute. Once again the media player, plus the large screen really help.
4. Email is far far better on the blackberry. It takes about five clicks on my iPhone to check multiple email accounts.
5. JiveTalk on the blackberry is awesome. I guess there will be plenty of 3rd party IM apps though for the iPhone
6. I love the iPhone keyboard and can type way faster on the iPhone than I can on my blackberry.
7. Heavy 3rd party app users will probably find a far better selection on the iPhone than the blackberry.
8. I love both devices, and the competition between the two will makes things better for the consumer.