It wasn't THAT long ago that they got rid of the 30GB model... and it looks like they've fixed it now on the store page. 20GB and 60GB only now on store.apple.com. It did say 30GB and 60GB yesterday, though.
Might have been an older graphic that came in the way. But the first post in this thread, I think, asks where the 30 GB went. And that hasn't happened yesterday, so I don't understand the thread's question, I guess...
Hehe, looks like one of those intentional leaks from Apple. The graphic is reverted to the original now, as in senne's original post which is the picture from Apple's server.