A Paper Leopard
I am disappointed by the new version of Apple OS X that was released this weekend. The UI has gone backwards in several areas. In particular, the translucent menus are hard to read, and the default "space theme" wall paper is ugly. So far it feels like a service pack with a bonus backup program.
I suspect that Apple is suffering from the same problem that Microsoft was with Vista, namely "How do you improve on a very good existing product?" In addition, I suspect the company's attention over the past year was focused on developing the iPhone, and perhaps not enough attention was paid to Leopard.
Still, I'm not sure what they could have done better -- Desktop OSs are pretty much of a solved problem. But I suspect that as the hype wears off people will start to question whether Leopard is a significant improvement.