The biggest roadblock to enterprise adoption of the ipad is its dependence on itunes. If you have to buy software, download software, sync software using itunes, a lot of businesses aren't going to be OK with that. Until Apple allows you to connect a USB to a computer or external drive, stick a disk in the drive and load the app, it won't fit well in big companies.
To all the people that say there is no place for the ipad in enterprise, you just aren't thinking hard enough about how to improve your enterprise. Of course I'm thinking somewhat in terms of tablet use and not just ipad use. It may be that Win-based tablets would be more appropriate, if they ever get the UI to the point where it works as well as the ipad. The fact that tablets haven't caught on that much so far is partly due to the insufficient UI and partly because of shortsighted IT people.