Asus Zenbook UX* line. Only thing that does not work out of the box with Ubuntu is ambient light sensor. Light, powerful, good (not awesome) battery life (4-5 hours), excellent display, ... Also Lenovo X1 Carbon, but the latest model comes with dumbest keyboard ever.
Battery's important. I'm aware of the keyboard issue on the Carbon. It worries me that they still have trackpad and keyboard issues in 2014. The X1 isn't the only one.
