When DH & I got married, I was 23 and he was 25, and though we'd been living together, we were still starting out in our jobs, etc., and were basically using hand-me-down stuff for the kitchen and cheaper stuff for the bedding/bathrooms, etc. We registered in 2 places - any more would've been a little silly, in our opinion - one of them was JCPenney and one was Bed, Bath & Beyond, which to this day, is still one of my favorite stores (love those coupons!). We thought we'd be making it easy on our guests so that they wouldn't have to guess at what we'd want, especially because we lived far away and had a completely different lifestyle than a lot of the family/friends that were coming to our wedding. Well, we did end up getting a lot of the "staples" on our two registries, but there were tons and tons of things (our registries weren't lengthy by any means) that we still didn't get, yet we got plenty of guests' choice items, which were odd, at best. What I thought was awesome was when people gave $ or gift cards, to be honest, since that leaves it ultimately up to us and they didn't have to go to the trouble of perusing our registry lists and picking out an item.
We did our own thing on the expensive china, so that wasn't something we asked for from anyone. Those formal china place settings are way too expensive!
Whenever I have to purchase something for a baby shower, DH & I always remark that it would've been great to have been able to have a gift registry for each of our kitties when we adopted them! Why not? Those are our "kids". Seems only fair to me.

Of course, now that we've been married a few years and our tastes have changed a bit (and we're still lacking some kitchen stuff we needed back then), we've joked that we should do an anniversary registry and have a celebration for "special" anniversaries, like the 5th (which we celebrated in Jamaica in 2006).