I went to this pagan/wiccan 5 day festival in upstate NY called starwood about 3 years in a row when I started dating the girl I'm about to marry. It's not nudist, but it's clothing optional, and a good % of people walk around with nothing on. I was nervous about being there, and after the first 15 minutes I thought nothing of it. As someone already stated, it's not about being sexy (it seemed there was nothing sexual about it at all), it's about being natural. Women are a lot sexier in clothes.
As fer me, first year I wore clothes the entire time. 2nd year the men's showers busted while I was all soaped up, and I had to walk to the coed showers and hop in an outdoor community shower where lots of guys and girls share shower heads. In all honesty I was real scared, but did it with no exciting incidents, and felt liberated after that. I didn't run around naked, but I became comfortable enough to take part in a couple of the events there that required nudity. It was an awesome freeing experience, and there was nothing sexual about it. At all.
Not sure how I'd feel if I were to go there again.