I've got one still in its box awaitiing my birthday next week.....
I ummed and ahhed about it for ages, but having got my hands on one recently thought that it was a great bit of kit.
I have an iPad, but this is a lighter, dedicated reading tool, although I am only getting the wifi version, the 3G is free worldwide (or where it exists!) and you can browse t'internet on it quite adequately (if you dont mind monochrome).
The kindle website has a lot of very cheap books but I agree some are priced stupidly and I think it may be something to do with dollar/ Sterling exchange rates.