... 5.11 Rush 24 ?
I've tried so many backpacks to cart around my tech over the years and the Rush 24 is by far the most robust, comfortable and useful bags I've owned.
Looks like it will last forever and although it looks a bit "mall ninja" in black, it doesn't really stand out in a commuter setting.
Fits an X230 in the hydration pocket, a 13" MacBook Pro inside the main pocket and an iPad in the front pocket, along with all the cables, a jacket, umbrella, camera and my lunch. It can even stow a bottle of wine in one of the side pockets too :) That's a bit extreme and I very rarely cart all that around with me (esp. the wine!!), but it can do it if I need to.
The side compression straps make it fairly thin when not lugging much about, but allow it to grow substantially.
I've stuffed it full of clothes and used it as carry on baggage too.