A few years ago, there wasn't much choice available if you wanted to read a non-traditional book. I had one of the original Rocket eBooks and I loved it. But, alas, parts became hard to buy. Since I edit also, I opted for an iPaq Pocket PC so I could read for pleasure, or work on a manuscript and sync back to my computer. Eventually, it's battery wouldn't recharge, and you know how hard it is to find batteries for technology more than a couple of years old!
I can read on my laptop, although it is a little less transportable than either of my first two readers. Now there are Kindles (available at this point only in the US right now) and the Sony eBook Reader (already with a new version), the eBook Reader from Bookwise and coming soon a new reader from Plastic Logic. I can also download and read on a Palm device, mobile phone of some kinds (like iPhone), and I'm not sure about the new netbooks.
There are plenty of options to the traditional book, although many still like it. I find, especially with a hard cover, that my hands will ache after holding a book for a while, and reading in bed with the light on is a worry for me since my SO has to get up quite early each weekday, so a backlit reader device is a good bonus for me.
Time to look around for a replacement!