I was at Best Buy for about 10 minutes playing with one. I must say, yet another device I didn't know I needed, but know can't live without.
I tried some of the iWorks apps, and they look really nice. The keyboard in landscape mode was great to use - it will take a little time to get used to not having a tactile feedback, but it's not bad.
The iBooks looks cool - the interface was nice, it looks easy to follow along. The iPad itself was a little heavy to use one hand holding it up while reading in bed, but it wasn't bad.
Surfing the web was great. I couldn't test the email because the demo unit didn't have email set up. But the calendar was great. Watching a movie was very nice as well.
The apps were all very responsible, very snappy. The display is great, a good size to have sitting in your lap. All in all, very well done by Apple.
I really think that not having a front facing camera for video chat is a bad move, but I wonder if there will be some way to link an iPad and iPhone together, and use the camera on the iPhone? That would be pretty cool. I would also love to see some other ways to link iPads and iPhones, to share files, music, pictures, etc. You can probably do it via mobile me, but I would love to see some kind of direct link.
I will be getting my 3G, 64GB version in late April through work (I think using this on the road or in the field will be great, especially once I tried it in the store!). Till then I just have to wait, although maybe I can convince my wife that she needs one as well.