On this page I'll try to share some thoughts on what BE may and may not be useful for.
Reading books: BE is perfectly suitable for this need. It's especially useful for reading in foreign language because you can set up Haali Reader to show translation of a word by tapping it once. It sure beats using a paper dictionary! I can not even begin to imagine how much eaiser it would be for me to learn English if I had Haali Reader before..
Some may find that the screen is smaller than they'd like, but I don't find this to be a problem at all. The unit itself is about 3" x 5", and of course the viewing screen is only 2/3 of that area. The best strategy is to make the font very small (10 pt), and the hold the BE close to your eyes: BE is so light your hand never gets tired. I've already read 5-6 books full length books on it in very short time and it's just as good as reading a paper book - perhaps even better, because it can fit in a shirt pocket.
BE is perfect for taking short notes. There is a program (tombo) for taking hierarchical notes, similar to how tree view in windows explorer works. This is also known as an outliner program. It would be difficult to type more than a few sentences in one go on the small on-screen keyboard, though - but it's easier than I thought at first.
BE is very good for keeping a todo list. It's very basic - there's no way to sort items except by priority or by name, but it's useful.
BE is pretty good as an alarm clock, even though sometimes it's too quiet to wake me up.
BE is fairly good for reading saved web pages, but some pages are hard-coded for wide displays and it's difficult to read them. It makes more sense to save them as text files and read them in Haali reader. Both available browsers have some disadvantages, unfortunately - you can read more on that in their respective sections.
BE can be used to read e-mails, but I haven't done that so I'm not sure how easy it is.
Last and Least, games.. you can have your Chess and your Go, and for the adventurous amongst us there's always Nethack. The latter is fairly difficult to control because it often makes you use keyboard, and you need a few key-clicks to do some basic actions like looting a box.. But it's very much playable, nonetheless.