I waited in line for the iPhone 3G. I had actually bought an iPhone just a few months ago, but wanted to upgrade.
I didn't really know why: I just figured the next version of what Apple was doing could only be cool. I'm a Mac fan.
As I wrote here, however, Apple and AT&T completely botched the activation process, leaving me without the iPhone 3G and, frankly, without much desire to undergo the ordeal again. Apple continues to ration the iPhone 3G for AT&T stores (the one place where you're pretty much guaranteed to have the phone activated), while its Apple retail stores are awash in the iPhones (but also awash in activation problems).
Meanwhile, I've yet to talk to anyone that can point to a clear, compelling differentiator between the new iPhone and the original iPhone. Yes, it's faster, but I spend most of my time around Wi-Fi and not enough time around a power outlet to care as much about 3G as I thought I would.
Indeed, the Web is swarming with lots of reasons to not "upgrade" to the iPhone 3G. Poor battery life, difficulty switching between 3G and 2(.5)G coverage, and a buggy and not-so-great 2.0 software experience whether you're on the 3G or 2G version of the iPhone.
Apple relies on an emotional response to its products to sell them, at least initially. For example, once you've used OS X you'll never go back to Windows, but that first leap of faith is just that: a leap of faith that you're willing to take because the UI is so beautiful. You recognize the power after the purchase.
If Apple continues to screw up the initial, emotional connection to its products through activation issues, buggy software, etc., at some point it's going to hurt its sales. I'm a Mac fan, but I've decided to pass on the iPhone 3G for the foreseeable future. I imagine I'm not alone.