I'm looking to buy a cheap HDMI that can pass 1080p video and Dolby 5.1 audio. Will any old HDMI cable work or does it need to be version 1.3? thanks

Buy a 1.3a certified from Monoprice or Blue Jeans Cable if you're paranoid. Chances are your normal cable will work perfectly.

How far are you going? If you're not going very far, practically anything will work. If you're going really far, a high quality cable becomes more crucial, whether it has the 1.3 label slapped on it or not.