I used to be what you'd consider "pro-life", but when a friend asked me what would I do with all the babies born that aren't wanted by their mothers, born addicted to crack, or any of a number of horrific birth defects. There's only so much private charities and the like can do. It's certainly true that since Roe v. Wade, a potential Einstein or Jonas Salk has been lost, but it's equally true that the next Manson or Dahmer was prevented as well.
I don't like abortion (what sane person does) and I believe that late-term abortions should be banned entirely, but I don't believe that a woman should be forced, by gunpoint, to have a child especially in the case of rape or incest. Just to make myself clear (lest the religious zombies go crazy) all options should be explored prior to the decision to have an abortion. I think that the "morning after pill" should be as widely available as condoms. I'd also like to have an agreed upon time at which "life begins". I don't believe that it's at conception, like droski said, at six months a fetus is capable of surviving outside the womb.
I'm sure other people wrestle with this issue the same way I do. It's just not a black and white situation and neither the religious zealots nor the militant pro-abortion crowd help the debate with their inflexibility.