John Gruber, in the "anticipatory lull" before tomorrow morning's keynote:
I haven’t been this in the dark about what Apple was set to announce in a keynote since the original iPhone introduction in January 2007. I’ve seen some speculation over the past few days that Vesper’s UI was informed by advanced knowledge of iOS 7. It was not. In fact, if anything, I expect Apple to zig where we (Q Branch) have zagged stylistically.
As I tweeted a few minutes ago, I've been so looking forward to Tuesday's adventures, with The Talk Show live and Beard Bash, that I've almost forgotten that the keynote is tomorrow. Exciting times!
iOS 7 is the biggest deal, but as Gruber mentions, lest we forget about Mac OS X 10.9.
See also: this tweet from Steve Streza.