My DH and I have never done registries. I have used then for other people, but it irritates me when you see things that are over $1000.00 on them. If people are going to be spending that much, they are close enough to you, (ie. your parents), that you can give them a hint. I have never heard of a parent buying off of a registry for their kids. I could be wrong though.
We didn't do a registry for our wedding, because we had most the stuff we needed, and we hoped that people would chose to give money instead. (Is that like evil?) We didn't ask any one for anything, but we know that people are going to give gift at a wedding. It worked, and didn't work all at the same time. We got a lot of money, and were able to buy coffee tables and our TV, but we also had a lot of tacky picture frames to return. That didn't bother me though.
For my daughter's shower, I told my Mom that I wanted a Marathon, and she had all her sisters put money in for it. (It is almost a $400 seat here in Canada, and my family is not well off.) It was the perfect gift, and I didn't have to "register". But I am not offended when other people do.