iPhone v2 and AT&T Plans

So, with the rumors of an iPhone v2 with 3G capabilities and maybe some other bells and whistles, what will this mean for existing iPhone owners. I assume many of us will be waiting in line again and “upgrading” to a new iPhone when the time comes. But what about our 2-year commitment to AT&T? I see several possibilities.
The worst case scenario is that you have to sign up for another 2 years. So if you bought one year ago, and then upgrade to iPhone v2, you have to add another 2 years to your contract. This is unlikely.
The best case scenario is that nothing changes. Getting iPhone v2 is just like replacing a broken iPhone right now. You just transfer your sim card from one to the other, and your standing with AT&T doesn’t change. I see this as somewhat likely.
When my SideKick II broke a few years back, I bought a new one. I had the option to pay the full price for the SideKick, or pay the discounted price, as long as I added another year to my contract with T-Mobile. So you can see where the worst case scenario isn’t that far-fetched.
Another option would be that you have to restart your 2 year contract with AT&T. Could be.
I think the one certainty is that there will be confusion. When the iPhone plans were first announced, a lot of people complained about the $59 (really $70) plan as a one-size-fits-all thing. You could add extra minutes, but that was it. Now, there are many more options, including family plans and, data-only plans, purchasing extras like unlimited text messaging, etc. I personally hate this. I think the only reason that most mobile phone plans offer so many options is that the phone companies hope to confuse us into spending more money. AT&T offers all sorts of plans for unlimited voice and extra features, but it is unclear which work with iPhone plans. Not that I get anywhere near the 450 daytime minutes on my iPhone anyway.