I have to agree the XPS 13 is perfect for linux. I have been using the XPS 13 9333 for about 3 years now. I run debian, 7 but now 8, and it just works for most things. I had to install the firmware for the wireless card but that was simple enough. I just got the new XPS 13 9350 a couple of months ago and am using that daily running Debian 8. I had to add the firmware for the wireless, base broadcom controller, and it…
If you want 32GB+, need a gaming notebook: P series from Lenovo sucks for linux (keyboard and touchpad).
We are basically left with Asus ROG machines. They're very comfortable to work on and touchpad is great, but really heavy and battery lasts for ~3-4 hrs. However, they have a fast Nvidia card for neural nets + can run 5 VMs at the same time.