All of the “HD” Kindles sport what Amazon claims is much faster Wi-Fi than any other tablet out there, due to two Wi-Fi antennas in each device and an algorithm that somehow crunches numbers to utilize signal echo in the data stream. They also have new support for Exchange email, along with Gmail and other webmail providers, and “Exclusive Dolby audio and dual-driver speakers” that nobody has really had a chance to test (the event was held in an airplane hangar). They are, in other words, a step closer to a general purpose, even productivity-minded device than the original Kindle Fire, which was built, pitched, and accepted as an entertainment delivery device.
It’s hard to boil down all those factors and see which Kindle best fits your palate. Personally, I think the 7-inch Kindle Fire HD is the best value. It’s not much more than the standard Fire, but the speedier Wi-Fi and crisper screen are worth $40. More than that, and more than anything about tablets, really, the money you spend should reflect what you believe to be the value of your free time. When you, as a working, responsible adult, find yourself with free time, is it usually when you’re in a living room, where there’s a much larger screen waiting? When you’re in a waiting room, a coffee shop, or another public spot where sitting is expected, is your phone usually enough for you? How much time do you really have between casual phone checking and sit-down streaming enjoyment?
For some people, the answers might actually indicate that, yes, a nearly 9-inch screen is something they want to have around, to enjoy all those moments in which Captain America: The First Avenger can be enjoyed with dual-driver Dolby sound and a nearly Retina-sharp screen. Otherwise, I think $159 is perfect for those with kids, $199 for those without.