One of my yorkies is AKC, I decided to register him. I guess it really depends. I think it's important to have the pedigree. (That's the only reason I registered) I'm only planning on having them as pets, but just for my knowledge and assurance - having the pedigree is a plus. It's sort of something I can put in my scrapbook or their special folders.
I treat my furbabies over the top though. I'm a crazy dog woman!
MY other yorkie is part of Japan Kennel Club, and I have her pedigree so I have no reason to transfer her over to AKC.