Well, I have had my iPad for about a week now. My initial thoughts -
In general, this is great for media. I use it much more than I ever used my iPhone for surfing, watching video - even listening to music. I have even started reading an ebook on it - the first ebook I have read.
The apps are pretty good - the new larger screen size really makes a difference, even with familiar apps and the built in applications. However, the higher cost of apps means I am less likely to go on a buying spree, just to try something. With the iPhone, I would be happy to put down $.99 or $1.99 just to try something - I am less likely to do it for $4.99 or more.
The hardware is nice. It is amazingly responsive compared to my 3GS, just as the 3GS was much more responsive than my iPhone 3G. Everyone who has seen it surfing the web has remarked about the speed. The keyboard is fine to use - I am even able touch type on it to a degree. The screen is nice and crisp - my wife was amazed at the clarity and resolution.
Issues or concerns - I don't see this replacing any other device I have, except for maybe the iPhone. Because it requires a computer to sync, I still need a computer, and since I still have the computer I still use it as my go to device for computing activities. This may change when I am travel, but I am not sure. For recreation, I am using the iPad a lot more, and it is replacing my iPhone at my "relaxing" device.