I think the obvious answer is Ipad.
Let's start with basic
pricing:
Kindle DX Wireless Reading Device, Free 3G, 9.7" Display: $379.00 (
http://www.amazon.com/).
Ipad Middle Priced with Wi-Fi and 3G plus 32GB: $729.00 (
www.apple.com)
Price differential: $350.00
Functions:Kindle: Download Books, Newspapers, and magazines. Stores books bought in online library to be downloaded anytime. 3G capabilities to check twitter and what not. Books can be downloaded in under 60 seconds. No glare screen. The perfect piece of equipment for the serious book reader. 9.7" inch screen (Black and White).
Ipad: Web Browser, Email, Photos, Videos, YouTube, iTunes, iBooks (Apple's version of Kindle. I know on my ipod there is a kindle app but not sure about Ipad), Thousands of Apps, Map system for directions, Notes, Calendar, Contacts, Built in Speakers, 9.7" COLOR screen.
Main Differences: Ipad offers the best of all worlds for just a 350 dollar difference. You get a color screen with built in speakers for watchign videos or listening to music. Kindle offers no speakers or color screen but is great for reading books.
Overall I would suggest Ipad if given the choice. Shorter battery life but lots more you can do.
Most the features were taken from respective pages.