One of the main challenges with using an iPad is data entry. If you need to write anything of any significant length you will want a keyboard and while the iPad supports Bluetooth keyboards, there hasn’t been many available. I own the Apple Wireless keyboard which is great, but it is not as portable as one would like. A couple of folding keyboards exist, such as the Freedom iConnex and the Matais Bluetooth Folding Keyboard, but using them means carrying two items, the iPad and the keyboard. A better option may be the Kensington Bluetooth keyboard case.
Inserting an iPad into the case, which has a built-in Bluetooth keyboard, results in a form factor that looks very much like a notebook computer. As you can see in the picture on the Liliputing web site, the iPad is in landscape as the screen and the keyboard at the bottom. The case and keyboard folds up into a portfolio, resulting in one piece to carry. One problem that I see with using this case is that it is probably difficult to use the iPad in portrait. The Kensington case will cost $99 and is slated to start shipping in October. A couple of other lesser known companies have similar cases at slightly higher prices.