There are a few variations of the touch screen laptop. One of the more common and popular versions is the convertible laptop that has a touch sensitive surface on the screen and allows the screen panel to be turned and fold on top of the casing to look like a true table PC. Pros of this setup are the strong processor and relatively long battery life, usually in the 3-4 hours. These are usually normal laptops with the adjustable screen and touch recognition.
It makes general tasks that are otherwise done with a mouse on long journeys to be done in a more convenient way than using the touch pad; multi-touch screen input really makes taking notes or browsing easy. When using on a desk they're easily sold as a normal laptop with all its upsides and downsides and some added functionality, like hand written signatures put in on the screen directly.
Netbook Convertible Tablet
Slate PCs on the other hand are true portable touch screen laptops, as they have no keyboard, touchpad or other input devices than the (nowadays) default multitouch screen. These computers make a great companion for anyone on the move and on their feet while in need to take notes. Taking notes for most people still means a piece of paper and a pen, but slate computers try to get rid of that conception.
Taking notes using a digital pen is now easy with these small portable computers, organizing them is just a click so there is no need to have separate file on the shelf for all the hand written notes. Slate computers come with a hand write recognition software to make data input more simple, but advanced on screen keyboards are also available.
These computers are true tablets, but normal laptop computers too, in the sense of extensibility. There are multiple USB ports installed on the casing so adding an external keyboard and mouse while using it on a laptop computer stand is relatively simple and a convenient way of work. Usual ports are available on these computers, DVI, D-SUB video and USB ports as well as microphone and speaker jack, kensington lock slot and card readers.
Slate PCs are light and easy to carry around, without extra touch pad, or keyboard manufacturers managed to cut the weight down to 2.5-3 pounds and that's light enough to carry around at all times, even while on foot. One of the most recent interpretations of the tablet computer is the new iPad by Apple. Will it be a hit or a fail, we've yet to see, but it's only a matter of time.