I LOVE my Kindle.
It's extremely portable, holds a charge forever, I can read it with one hand, and if I finish a book - I can buy another and have it delivered in a jiffy.
I've had my Kindle for a couple of years now, and treat it pretty rough. I no longer use the leather carrying case, I carelessly toss it in my purse every day, and I've taken it to windy-sandy beaches more times than I can count - but it still works perfectly.
Recently I decided to upgrade from the 1st generation Kindle to the newest version (3rd generation), mainly because the newest version is thinner, lighter, can hold a charge for a month, and gets wireless globally. Since we travel a lot and my Kindle always travels with me, I like that I can buy a new book almost anywhere.
With the incredible decrease in Kindle pricing (1st generation was $350+, now you can buy a wi-fi only version for $135) - I highly recommend buying a Kindle if you're a book lover.
Once you have one, there are a ton of free and inexpensive books (>$5) - so, unlike when the Kindle was first released, you don't have to spend $9.99 on every book you download.