No AppleCare here. AMEX provides me with a year of additional warranty coverage for manufacturer's defects, and I have yet to ever damage an iPhone. Even if I did manage to break a screen, it's only $129 to replace at Apple, which is the same as AppleCare + with the $29 deductible. So you only come out ahead once you've cracked your screen multiple times (or of course if you sustain other damage- I'm not concerned about that).
I understand some people just are harder on their phones, or have kids, etc... where it's a no brainer. Just not necessary in my case.