It seems to me that her "misstatements" fall into two categories. One is the garden variety politician's double-speak -- "she supports drivers' licenses for illegals / oh no she doesn't" or "she voted for war with Iraq / she voted to authorize diplomacy" are typical. Unsavory, perhaps, but sadly not all that unusual.
The other type, to me, is far more disturbing. Like her Sir Edmund Hillary fable, Hillary's statements about sniper fire in Bosnia are lies that aren't even politically "necessary" (unlike, arguably, the ones above). They're just something she's said because it's expedient -- they sound good at the time or she perceives them as bringing her some momentary advantage. In a sense, they're "optional" lies.
That's what's so unsettling about them. Someone who resorts to "optional" lies is someone who really doesn't mind lying at all and does it without a second thought -- a disturbing trait in a would-be president. What's more, when the person doing the lying is a First Lady, who must be aware that her every statement will be checked for its accuracy (and that tape or other evidence probably exists that will permit disproof or verification), the fact she's willing to lie suggests one of three possibilities, none of them good:
(1) She isn't very smart (what? you've got footage?!)
(2) She doesn't think we're very smart (oh, they'll never find out!)
(3) She can't help herself