I am surprised about all the hostility towards getting a prenuptial.
1) If you are worried about whether or not she will say yes when you propose, you should not ask her. The act of proposing should be nothing more than a formality. Something romantic that will be special for the both of you. Also, be a proper gentleman and ask her father's blessing in advance.
I am constantly amazed at how many people get engaged without having a lot of serious discussions about the long term. There are many, many things you and your girlfriend ought to have hammered out before you ever entertain the idea of marriage. Examples include but are not limited to finances, long term goals, how many children, how you are going to raise your child, religious differences, end of life or ICU morality decisions, etc.
2) There is not such thing as "the one" or "soul mate." In reality, there are only a few thousand girls out there whom you are truly compatible with. When compared to the millions of available females, finding and successfully wooing one of the few thousand females with whom you are truly compatible becomes quite the daunting task. Thus, giving us the illusion of finding "the one" or our "soul mate."
3) This notion of a happily ever after ending is a quite tragic metaphor that our society has been brainwashed into thinking is true. Reality is that two people with different backgrounds, thoughts, experiences, beliefs, etc. are coming together to share a life together. This is not an easy feat. I think too many people underestimate the difficulty involved. Furthermore, in addition to committing yourself to another being for life, you are suppose to start a family with this person. This only complicates matters.
4) People are dynamic. We are constantly changing and evolving. Some of us for the better, some of for the worse. I think this is the scariest thing about marriage. For a moment, lets concede that you have indeed found one of those few thousand girls which you are truly compatible with and vice versa; it does not necessarily follow that she or you will be the same person five, ten, or twenty years down the road. Some food for thought.
Given points 1-4, I think getting a prenuptial is not a bad idea. It is a non-issue if you are married "until death do you part." Statistically, you have less than a 50% shot at being married until one of you pass away. If you do divorce, wouldn't you like to have an agreement already worked out? An agreement in which both of you worked and agreed to when both parties were thinking clearly and rationally? Once a couple gets to the point of divorce, emotion takes over and rationally is tossed to the curb.