I thought Ruger was so cute when I got him I took him right to the groomer and asked if she could make him look the same when he was ready to get cut. She told me it was a standard puppy cut, so that's what I'm going to do. I think they look cute when they're a little ratty looking.
That said, I've seen some photos here of Yorkies with long hair that look incredible, but I'm not sure I want to go through that level of grooming.