To be fair, the Macworld Expo site has *no* information about who will be presenting the Keynote. Apple hasn't officially announced it yet. We all just assume it will be Jobs.
I really think it will be Jobs, but as has seems to be the case he is increasingly giving time over to others because Apple as a company can't survive just on the power of Jobs. But I definitely think he will give part of it. The speculations that he is on his deathbed will run rampant if he doesn't.