Amazon just introduced new Kindle Fire tablets, including a revamped old version that costs $159, and is both faster and has longer battery life, as well as two Kindle Fire HD models, one with an 8.9 inch display and one with a 7-inch display at a higher price point, but with Dolby Digital sound and high density displays.The HD models have a TI OMAP 4470 processor, as well as improved Wi-Fi performance thanks to two antennas to cut down on signal*interference. The resolution on the large HD Fire is 1920x1200, and there’s a laminated touch sensor on the screen to reduce glare and produce sharper, better contrast.