There are 3 distinct camps within the Tablet PC market:
Slate style tablets, eg Apple iPad
Convertible Laptops, eg Dell Duo
Booklet Tablets, eg Microsoft Courier
Slate tablets are very popular due to their ultra-portability and the market leader, the Apple iPad, incorporating the best touch screen in the world. However, they lack real computing power and tend to be used primarily for entertainment, internet & e-mail applications and general organization.
Convertible laptops are more powerful than their slate cousins and are capable of running full applications on a windows platform. This means that you can work and play on the same machine. As a result they are heavier and bulkier than the slate styled tablet. Price has dropped dramatically in recent times due to the manufacturers having to compete with the success of the iPad which means that this form of tablet will become more and more popular as the size and weight decreases with technological advances.
Booklet tablets are relatively new and most are still in the development phase. These are generally much link the iPad but in dual screen format, almost like holding a book. Again it is expected that these will have much less computing power than a convertible laptop and be used primarily for reading e-books, e-mail and internet browsing. Unlike the above mentioned convertible laptops and slates, most of the products planned then far only support stylus input on the screens.
For fun and games with a bit of social interaction, get a slate style tablet, the iPad being the best available at present. For real computing power with the dual modes of laptop & slate, get a convertible laptop tablet PC.
The latest development in this market has been the release of the Dell Duo; the first netbook sized convertible PC. Its reduced size counteracts some of the issue relating to heaviness and it comes with a dual processor and innovative conversion design.