I agree that abortions should be limited to the 2nd trimester at the latest, and ideally the 1st. That is one reason I think abortions should not only remain legal, but become less of a taboo even among religious conservatives. The more acceptable abortions are to pregnant women (many of whom are only teenagers), the more likely women are to get them promptly with minimal risk to their health, and far less fetal development.
I also agree that abortions should not be done indiscriminately, and therefore some restrictions should be placed on how many can be done and in what circumstances (e.g. sex selection isn't a valid reason, but perhaps it's appropriate to prevent a defective fetus from becoming a vastly disabled human).
Of course, sex education (at both school and at home), and easily accessible contraceptives, are critical to cutting down the number of unwanted pregnancies, and therefore abortions.
I think we're actually not so far apart on this issue, as although I am "pro-choice", I am ALSO very "pro-life" and of course want the best possible life for all babies born into the world. The reality is, that is not always possible, and so in some circumstances abortion is not only acceptable, but perhaps the merciful thing to do.
I don't think McCain/Palin respect the all-important grey area on this issue, nor are enlightened enough to seek more fundamental solutions to unwanted pregnancies (e.g. better sex education, more widely available contraceptives). I think criminalizing abortion outright is a truly wrongheaded pursuit that will only lead to lots of "back alley/wire coat-hanger" abortions, not to mention an increased burden on society.