In general If running Linux be sure the GFX is Intel especially if not playing games. Nvidia and ATI is pain in the ... atleast what I know of.

I would recommend Lenovo but latelly they have been less good , as already pointed out by MartinK above, so be carefully when choose exact machine if choose new Lenovo.

I Have a X230 at home and love it. It's weight is low with 13.5" and I choosed it with IPS display. The resolution is little to low this days 1366x768.

Then there came X240 do not buy X240. No physical left/right buttons and the touchpad is horrible). But now they have released X250 it's seems better I would probadly go for that myself if I needed new laptop.

On my work I have a very heavy http://shop.lenovo.com/us/en/laptops.../#tab-features And I don't like it. touchpad is same as X240.. Also the GFX is kinda PITA if using dual screen. The internal display resoution is to high IMHO but with IPS(good) If I remember correct display is 2400x something...

I also got it with dual GFX Nvidia+Intel but the closed Nvidia driver is crap when using it with dualscreen. It's some tweaking with GFX drivers working if using linux.

In general I recommend:

* do not choose to big screen it just hurt your eyes.

* dualscreen seems half broken in linux latelly but probadly a bit offtopic because I guess this is problematic whatever laptop you choose. And maybe you don't use ext display anyway so..

* If not gaming, cadding: Choose Intel GFX to avoid as much as possible problems with GFX.

* Personally I choose open GFX to make sure it works with nextgen display servers (means wayland)

* Do not choose less than 256 SSD or buy hybrid as some says in the thread.

* Choose a big battery so you can use it all day without recharge,