I actually don't see tablets replacing laptops any time soon. I see tablets developing more laptop type features (like a keyboard docking station) but I agree with Jobs that you'll see 2 distinct requirements. Daily vs heavy use and a OS offering to go with each.

IMHO, in a few more iterations (1 or 3) the iPad will be robust enough to handle the daily needs for most standard users. Power users will of course need something more powerful.