What hdmi cables do you recommend for 8ft cables for the best picture and audio quality?
As long as the cable is certified as a High Speed cable you should be fine with any cable. The key are the words "High Speed" and "certified". Basically there are only two types of HDMI cables - standard speed and high speed with some options.
The cables transmit bits as electrical signals, so as long as you don't have errors (and you'll know if you do) the output signal will be the same. I wouldn't pay more than $12 for a good 8ft cable.