Definitely worth it for me, and my problem was just a fluke that
Amazon took care of with one less than 10 minute phone call. I purchased mine the first part of March, since then I have devoured probably 10 or more books, msot of them free from the Kindle site. I also utilized points accrued by my bank's Visa check card (we use it almost exclusively) to get a $100 Amazon.com gift certificate that I have used to help feed my reading addiction.

On Sunday morning I turned my Kindle on after charging it overnight. An approximately 1 inch long section of the top of the screen was distorted, almost like bleeding over from prior pages. I called Kindle support and the guy talked me through some rebooting steps, which did not alleviate the problem. He confirmed my customer info and said "your replacement will ship out tomorrow(Monday), next day, you should have it on Tuesday. I'm emailing you a return label for UPS to ship back the defective unit. Sorry for you inconvenience." Painless as that. I wish everything in life was that easy, so yes, I would say it's worth it. I have not fully explored all of the extras on the unit, but there are several other DIS members here like DVC Liz that were super helpful and encouraging to me as I contemplated the purchase.
IMO, if you have the disposible income to afford it, by all means, do. BTW, if you have an iPod Touch or an iPhone, you can download the Kindle app for those devices for free.