I'm for pre-nups. One thing many people don't consider is that if done in the right spirit, they can be selfless, not selfish. For instance, you can structure it so you're saying, "I care for you and even if our marriage somehow doesn't survive, I want you to be provided for. So this pre-nup ensures that I won't make any claim on the assets you brought into the marriage, and that you'll have support to get back on your feet." In other words you don't have to make a pre-nup to protect your own assets. You can make it to protect the other person's assets. If both people do this lovingly and of their own free will, I think it can be a great sign of caring.
I had a pre-nup, and my soon-to-be husband showed his true colors at the arrangements. We went to my lawyer, who had prepared the pre-nup, and he said, "I don't need to read it, I'm sure she's fair, where do I sign?" We had to convince him that he needed to have the thing overseen by his own lawyer (or else there's cause for arguing, in the event of a divorce, that "it doesn't count because I didn't know what I was signing"). But he trusted that what we put in there was fair, and it was. As it happened, the marriage didn't survive. But he's never tried to bilk me out of any money or act vindictively, nor I him. Both those traits were reflected in our pre-nup experience. (Our divorce lawyer did say that the whole process was made much less gruesome by the pre-nup, so it was useful that we had gotten it.) The people who fight like cats and dogs over the pre-nup -- it makes me worry that this is indicative of later distrust and lack of generosity and cooperation.