I know plenty of medical staff who are receiving training now to use iPads as the sole computing device in the hospital, for example. Same for a lot of financial companies.
Microsoft is trying to sell the idea that you can have the best of both worlds (traditional PCs and tablets) without sacrifices but its simply not true. Something's gotta give. In the case of Surface I expect a lot of frustration trying to use a standard windows app on a small touchscreen. And if you are going to connect the device to an external monitor, keyboard and mouse, you might as well have a small desktop PC.
this is not new, either. Microsoft has tried time and again, first with TabeltPCs, then the overhyped UMPCs (remember those?) and its always hitting the same walls.
If you are going to do a big change in the paradigm you have to have the balls to do it completely and take the advantages that switching to a "pure" tablet experience can offer. Leave bloated software behind, leave all the legacy support, etc...