My fiance proposed twice, (no, I didn't turn him down the first time) but the second one is the more romantic story
When he proposed the first time, we were both broke college students, so he couldn't buy a ring. He wanted to though, so we started looking together.
We spent that summer apart because he had a job and a lease in our college town, and I had an internship in our home town. He came to visit me over Memorial Day weekend, and we went to the mall. He took me to all these stores to look at engagement rings, then took me to dinner before we went out to the movies. We were seeing the opening showing of Pirates 3, so I was really excited.
After the movie, around midnight, he asks me if I want to go to the dock at Lake Occoquan. I was in a pirate haze, so I just said yes, thinking nothing of it. Pirates, water, it made perfect sense to me.
So we walked down onto the dock, and he turns to me and says, "I need to be honest with you... this whole day was a lie." I had no idea what he was talking about. Then he pulled the ring out of his pocket, and told me that he had already bought the ring, got down on one knee, and asked me to marry him. I was stunned, because I really didn't think that he'd bought the ring already! It was so sweet!