I believe there are diminishing returns in the demonization of conservative figures since the Left can yell "so-and-so is Satan!" for only so long before people detect a pattern. So I'm not sure the way Palin enrages the Left isn't a good thing. Call it the rope-a-dope strategy: let them punch themselves out.
They hated Reagan, they hated Gingrich. Some will remember that Karl Rove had his own star turn, earning opprobium for helping get Bush elected in '00. Bush himself became the devil until it seemed that Cheney was wielding power. Post-Cheney it's now Palin.
Palin brings especial terror because she's a new political animal: the populist pro-lifer. Scares the heck out of the establishment. She's Ross Perot with breasts -- and convictions about something beyond the deficit.