Amazon and Google will be going head-to-head this Christmas as both companies are looking to make a mark in the budget tablet market with their 7-inch tablets: the Nexus 7 and Kindle Fire HD. But which one gets you the most bang for your buck? Well, that's exactly what were going to find out. It might be the case that this week a third competitor will enter the ring. But until the iPad Mini become reality we'll blissfully ignore it for this face-off.