And as far as swappable batteries, I don't think I have ever seen in my human life someone swap out a dead phone battery. It's 2008.
My wife does this all the time when she's travelling with her Nokia. She takes two batteries and if she can't charge her phone, she just swaps the batteries out. When she's on the road (she's a newspaper correspondent), she lives on the phone... iPhone or regular phone, if you talk 5+ hours a day on the phone, you'll burn through batteries and if you are on the move in airports, it's not always that easy to find a place/time to charge. With the spare battery, she has 9+ hours of on-the-go talk time which is enough even for her.
I think it would be really nice if Apple would move over to removeable batteries. Yes, the lines of the device wouldn't be as clean, but it would mean that in 1-2 years when the battery starts to die you can replace it yourself instead of mailing in your phone. I'm glad to see the EU is pushing hard for all portable electronics to have a removeable battery - hopefully Apple will work with them rather than opposing them (or selling a removeable version over there and a non-removeable version here).
Still, all this said, everywhere I go nowadays seems have a Duracell or Energizer AA -> iPod/iPhone charging gizmo. I have seen tthem in the check-out line at Home Depot and Safeway. And you can get nice external lithium-ion battery packs for the iPhone that triple the battery capacity (while turning your svelte iPhone into a literal brick, but that's the price...). This is what I use and it works for me - and you can charge the battery on the iPhone while you are actually using it (try that trick with a removeable battery).