Looks like McCain had been seriously considering Palin for many months. I'd been aware of her since early this year, and knew she was at the top of a lot of right-leaning pundits' lists of "people McCain should pick for VP, but won't". This points to very good rumor control by the McCain team; a lot of people felt she should be the choice, but hardly anyone had a clue she was even being seriously considered.
It also points to bad opposition research by the Obama team, which appears to have been completely blindsided. For anyone following the Republican buzz even a little, the announcement was a considerable surprise, but not something that just suddenly appeared out of nowhere. (This may be part of a pattern; Obama doesn't seem to be prepared with even approximate answers to unscripted questions, even when those questions are the sort that a candidate or his team ought to anticipate being asked, on the basis of questions that have been asked in other recent campaigns.)
Now we're treated to attacks on Palin as anti-woman, because she doesn't follow the orthodox feminist party line: she's anti-abortion (a position with which I disagree, but which is more morally defensible than my own rather mushy position), and... well, I think the rest of the case against her boils down to she seems totally at home dealing with men on their own turf. Yep: she doesn't see men as the Enemy; ergo, she's an enemy of women.
I've had some fleeting exposure to small-town culture, with a minor refresher course lately. It's nothing like big-city culture, and, in many respects, preserves important traditional American virtues (about which there's an essay waiting to be written, in among the long-past-due Fargo trip report). Alaskan small-town culture seems to be an extreme version: men are men, women are men, and meese are scared. It's not surprising that, when someone from this culture ventures into the big city, she frightens the metrosexuals.
She also bothers the environmental lobby, which has turned into an institution run by urban lawyers and fundraisers, with no room for old-school conservationists... the ones who actually get out and enjoy the outdoors, and maybe eat bits of it. Outdoorsmen know perfectly well that wildlife habitat is also outdoorsman habitat, and that without moose habitat there'll be no more moose stew. The professional lobbyists just don't seem to grok this, and often regard hunters, fishermen, and even tourists as the enemy of some distant abstraction they call the environment.
So, she's annoying some of the right people, and fighting the crooks within her own party annoys even more of the right people. Both parties desperately need up-and-coming reformers; perhaps the Republicans will embrace them. (I have no such hope for the Democrats any time in the foreseeable future.)