Having recently acquired a 3G Kindle Keyboard, I've spent a fair bit of time exploring its capabilities. Yes, I have spent some money on Amazon for a few ebooks. (My first Amazon purchase took place in October 1995, so we go waaaay back.) Although I can check and send email and browse many websites, it's no replacement for a netbook -- or a smart phone, for that matter! The real attraction is best summed up by Randall of xkcd fame.
<a href="http://xkcd.com/548/"><img src="http://imgs.xkcd.com/comics/kindle.png" title="Kindle"></a>
Okay, pecking out that html on the Kindle was laborious and I'm not even sure if this posting method will allow me to do that. If there was no comic visible above, please go to http://xkcd.com/548/ to see what I was talking about.