I have a small Timbuk2 bag. Works very well for the iPad but the model I have won't accommodate a laptop, as well. Nevertheless, I've been impressed with the quality of the bag. My only complaint is the excessive use of velcro. Drives me crazy. But from what I can tell from the video of the new messenger bag from Timbuk2, this may not be a problem.
Have a Waterfield Cargo bag I've used for years. They wear like iron. I've had mine for five years, about half a million miles of travel and it looks as good as the day I bought it. Many options for interior sleeves and can accommodate both a laptop and tablet very easily. Expensive to begin with and expensive to accessorize. But it also outlasts almost anything I've ever seen by a factor of at least 2. A great bag but no longer my favorite because...
Got a Tom Bihn CheckPoint Flyer as a Christmas present. This appears to be similar to the Timbuk2 bag cited in the OP post in that both are TSA compliant. It is FANTASTIC. If you're looking for the Rolls Royce of bags for both laptop and tablet, this is it. Considerably more expensive than the Timbuk2 but it's manufactured here in Seattle and customers swear by them.
In addition, the Tom Bihn bag enables you to change laptops i.e. move from one size to another, without purchasing an entirely new bag. Just purchase another compartment to fit the new laptop.
I travel a lot and really wanted a TSA compliant bag to replace my Waterfield Cargo, avoiding the need to pull the laptop out of the bag in a security line. The Tom Bihn meets that requirement and rivals the Cargo bag in terms of volume.
http://www.tombihn.com/page/001/PROD/500/TB1701