I've posted this on another thread, but it looks like Dell is trying to make real laptops. The newest XPS ultrabooks have received rave reviews, and some of them even ship with Linux preinstalled [1]. That said, my personal laptop is a Lenovo T440s, because IMHO Lenovo still wins on upgradeability. I was able to buy a base model, and in short order had the RAM upgraded to 12GB (the max this model supports) and swapped out the hard drive with a SSD from Amazon. I'm not sure how feasible that is with any of the other laptops being discussed here.