E-Reader, scheduling assistant, drawing board, you name it. And what you can do on a computer, you can do on a tablet.
Tablets and smartphones are, because of their size, are often targets for thieves - small and easy to conceal, there is also a market for them that makes them easy to sell. And it's just easier to set down a phone or tablet and walk off, unlike a personal computer or laptop!
Many of the same apps that run on your phones will also run on your tablets. If you take your tablet with you often, consider installing an app that will remotely wipe the device. One thing you should do if it is stolen is to CHANGE YOUR PASSWORDS on all accounts that you may have accessed on the tablet. Especially if you have credit card information stored, such as on the Apple Store. This goes for smartphones, also.