It's an interesting topic, for those of us who want the cool device, but would also like to see some benefit from it in the work place. I went into it with exactly that attitude. I decided I would get the iPad because I wanted it first. I'm not going to even try to justify getting it for work related stuff, but if I can use it that way, so much the better.
I have found that it is helping me in ways I did not expect. First of all, our company has a very robust Cisco Wireless Network, which requires user and domain authentication to log in and broadcasts using an invisible SSID. Even with all that, I was able to connect to the wireless network using my iPad. I have to set all the right options and enter my username and password in the appropriate places, and I had to know the exact spelling of the invisible SSID, but it worked. I did not expect this. No laptop can do this without the appropriate wireless client installed and running from our IT departement. Yet the iPad connecting painlessly without any external help.
I have also found the Keynote app pretty useful with powerpoint. My job requires me each month to pull together data from multiple powerpoint decks and then use that as content in a final single version. In the past, this has me running up to six powerpoints on my PC and navigating between them, constantly being confused which one I am clicking on because the taskbar at the bottom abbreviates the titles too much and even with dual monitors, powerpoint won't let you look at two separate presentations at the same time on separate monitors. So now I send them all to my iPad, except the one I am working on. Keynote does a really nice job of organizing the presentations stacking them into easy to find "piles", and I can quickly navigate between them, finding the information I'm looking for, all the while having another one open on my PC which I can then edit.
I'm doing other things too like navigating to our corporate intranet, so that I can look up information while working on something else on my PC. It's quickly becoming a handy complimentary tool to things I do on a daily basis. I did not expect this. I brought it into the office the first day I had it to show it off, to be honest. But now I'm bringing it because I actually use it and would miss it if I didn't have it there.
Probably what a describe is a bit trivial or basic, but I honestly think it's value in the workplace is nowhere close to fully known yet. It's brand new technology. It represents a different way to be productive. It will take some time to figure all this out, but I am convinced it will have value, significant value for me at least at work.