Leopard "Preview" - TextEdit
Possibly the most unexciting component of Leopard. As of now, it's got only a .1 version upgrade. They could do something with the main interface though; it looks really ugly still.
Anyhoo, they have added OpenDocument support, which unfortunately, I did not want to test because testing it might have put me to sleep. I don't live under a rock, but I really do not know anyone yet who would be willing to share files with me in ODF. Go knock yourselves out!