Tom Bihn bags
I use a Tom Bihn Brain Bag rucksack, sometimes with one padded insert for a laptop (it's a bit *too* padded at times and takes up too much space, so I put my laptop in a Tucano neoprene sleeve then). It takes a laptop, Kindle, and iPad with oodles of room to spare. As BSAG put calls the smaller Synapse bag in her review, 'The TARDIS Bag':
My Brain Bag, even when packed with stuff, is incredibly comfortable to wear. Unfortunately, you won't be able to try one out as you order them directly from the manufacturer in the USA. Oh, the quality of construction is extremely good as well, with nice chunky zips, for example.