It's an interesting device.
While watching the live coverage (TWIT rocks) I was pretty excited, And was tying to plan out how to get a hold of one as soon as possible.
However after the initial Apple Euphoria wore off, I've had a few thoughts.
Price and Storage - While the initial Price $499 is low, it only gives you 16GB and no 3G. If you plan to consume a lot of media, especially videos You're going to need more then 16GB. I currently have a mostly full 16GB iPhone 3G and I hardly have any video on it as I need most of my space for Music, Photos and Apps. Most Videos I view start at 300Mb for a Low quality with good to HD between 600MB to 1.5TB.
So for most users, the Price is going to be either $599 or $729 with 3G for the 32GB and at that Price You have to stop and think. Add the cost of the Dock or Wireless keyboard if you plan to do a reasonable amount of data input At that Price point you're well above most Net book prices and there are lightweight Net books (2-3 Pounds) with 6 to 10 Hours of battery life available much cheaper.
iTunes - While the iPad's going to have smoother interface, its still designed as a companion device which you sync to iTunes. It can't be your only device. And Unfortunately while I'll use iTunes when i have to I'm not to fond of it and that's one of the things I least like about my iPhone.
Camera - The lack of feature that really would have gotten me to get it would have been a front facing camera, especially if it allowed apps like Skype to work. I could probably justify most of the price just for that as I relay on skype to keep in touch with both work and family, and we're slowly using video chat more and more.
Books - While I do read books on my iPhone (And My Laptop and the N800), I still prefer to read on a eInk screen as I'm able to read comfortable for much longer. As such the Ebook Store is interesting, its not going to affect me much unless Apple kicks off the other ebook reading apps. (By the way, if they do, I'm selling my Macbook and iPhone )
On the whole I don't think its going to impact the 5" & 6" readers as much (No more so then the Touch did) except put a bit more downward push on prices. For those who want a portable, pocketable reader they are either going to go for the Touch if they want backlit or for one of the eInk readers. The Bigger screen readers from Amazon, iRex, etc on the other hand are definitely in trouble, unless they are A) able to showcase some major specific advantages or B) Go down drastically n price.
Content creation - iWork was interesting. It give you a way to edit and create Presentations, Spreadsheets and Documents on the device itself which would be very useful for students, etc who may not need more advanced features all the time. I'm just curious how the files are going to be synced.
Photos - The Apple site says that You'll be able to connect it to a camera to transfer photos over. This is probably going to be very useful, but lets see how much the transfer capability is going to cost and how easy the transfer is going to be. If they allowed you to transfer photos (and Videos) from the iPhone it could be a killer combination.
On the whole, I feel I'll probably hold out for a second gen Device, unless there is something specific that I want to do that I can only do on it.
As a side not how many other people did a spit take when they showcased the Keyboard dock and though Microsoft and HP had the right form fact 5-7 Years ago with the
Tc1000 and
TC1100 and they abandoned it. If they come out with a similar one now, everyone ids going to say they copied Apple, though they did it first years ago.