You worry about whether Palin would be ready to be president, but she would be vice president. Obama is the presidential candidate and he has less executive experience than Palin.
Nobody on either ticket except Palin has executive experience, so the executive experience thing is non-starter as far as I am concerned. Furthermore, Alaska with its oil revenues ain't exactly the same as running another state.
However, you raise a very good point. The question of whether Obama is ready to be president or not is much more important than whether Palin is. He has allayed my fears that he won't do anything rash and stupid in an emergency. However, I worry that, like Jimmy Carter, he might dither when the shit hits the fan.
Furthermore, Obama's spending plans concern me immensely. We simply can't afford them, even with increased taxes. Unfortunately, I think we need to raise taxes and cut spending, but to close the deficit and pay off the debt. I fear he is going to raise taxes and raise spending. Health care coverage for all don't come cheap.