I used to have a Sony ebook reader - which was not bad. The lack of a complete set of Terry Pratchet books led to its dis-use and it is somewhere on a shelf now.
So now I have a Kindle, and I have to say they have done a good job.
Heck, you can even edit FireBrick configs on it!
Oh, and maybe I'll read some books, but once again they only have some of the Terry Pratchet books available which is totally crazy. Paper books do not suffer this stupidity - you can buy them all and read them in order (which I have done now).