I think you're bringing up a noteworthy distinction, UberGoober. There are a ton of iPads in the enterprise, but a lot of them are used as secondary devices for information access, as you say. One of the big research firms (Forrester, if I remember) even did a study that drew that conclusion-- that iPads are often used alongside, rather than in place of, traditional PCs.
That said, I'm astonished how often I see people typing on their iPads. At every event I attend, I see journalists and analysts typing away on glass screens. Not just shorthand notes—full paragraphs, often punched out at a surprisingly quick rate. Personally, I still want a physical keyboard in situations like that-- and indeed, conventional laptops (albeit with a higher-than-average MacBook representation) are still far more ubiquitous at those events. But it's clear that people are increasingly using tablets for content creation. I don't think there will be a tipping point where touchscreens takes over for "real work," or that physical keyboards are going away, or anything like that—but I've heard analysts say that more words will be typed this year on glass than on actual keys. I'm not sure if I believe that, but the fact that it's even close tells you that tablets are being used for more than watching videos. (Though I concede a lot of those words will be dedicated to vapid text messages and Facebook status updates on smartphones.)
For productivity tasks that require quick exchanges or that involve moving or slightly modifying information, tablets can actually be preferable to traditional form factors. I'm not going to get rid of my computers any time soon; I need them for substantive writing, spreadsheets, video and photo editing, and other tasks that don't tablets very well. But I think the "content consumption vs. productivity" debate involves a lot of rigid definitions about what constitutes "real work" and what doesn't. There are shades of gray, and tablets occupy lots of them.