I think the problem is that alot of people here on the boards spend so much time from "stupid" people trolling about that it becomes second nature for people to go on the defensive when someone asks why buy the phone and what's all the hubbub about.
I can tell you for me coming from a 3G it's speed, the screen, and the camera is phenomenal. I picked it up Thursday and then took my family to Universal for the weekend. It was so great to be able to take video and have the phone to take pictures. Admittedly I have a point and shoot but I was thinking of getting a Flip for the summer so I could get some video of my son but the video on the iPhone 4 saved me another 200 dollars becuase the videos look great.
Now I know that there are other phones out there that have been able to do that but none sync up to my Mac the way that I want them too. That's why I've gone with an iPhone in the first place - it syncs the way that I want it to sync. Also, I'm sure if alot of the people could have got a reservation or pre-ordered they most likely would have but this is their only option.
And then you have people that do it for the "experience". Admittedly I waited in line for the iPad and it was a really great experience. Now, I waited at an Apple store that provides a shopping experience on launch day that I think few other stores could rival becuase the employees at the Apple store really take care of you and add to the experience. For those waiting at an AT&T store I'm sure it's going to be a little different but when you want something...you want it. You don't always need a reason for the want.
As for what do people do with it...I think Forums aren't always the best place to look for what people do creatively with their phones. Check out Youtube or Flickr or other sites like that. I can almost guarantee you that within a month there will be scads of videos of people being uber creative with their iPhones...you can find scads of what they've done with the old ones - with the added tech in the new iPhone 4 that's only going to grow.
As you can tell - I am a proud and happy owner of my iPhone 4
