I have a Kindle-Keyboard, a Kindle Fire, a Kindle Paperwhite and an iPad with the Kindle App. I love the Kindle-Keyboard because it is not lit in anyway and looks fantastic when there is enough light to read by. The Kindle Paperwhite always has a light on - you can't turn it off, only down. Even in sunlight, the text is somewhat backlit and doesn't look quite as booklike as the Kindle-Keyboard. Once you get over that, the Kindle Paperwhite is great - touchscreen, the light is actually very good and you can read anywhere from direct sunlight to the dark, and it's a little smaller since it doesn't need a keyboard. The Kindle Fire is much more versatile, but _heavy_. I don't love holding it to read and always go get a lighter e-reader. And the screen is to small to really do Internet tasks on - I always go get the iPad for that.
IMHO, if you want a multi-purpose device with a reader, get something as big as the iPad, and if you want an Ereader, the Paperwhite is the best Kindle unless you plan to read using a lamp all the time, in which case I would get the old school Kindle ink, with or without the keyboard.