GNOME

I really love the simplicity of dwm (I haven't quite understood the difference between a WM and a DE). It's hackable and efficient and just the way it should be. It runs really well on my age old ThinkPad. For more user friendly environments (i.e. desktops which not only I use) and more performant machines, I still use GNOME though.

If you haven't tried them, I recommend giving them a try. They all have something to offer.

I don't use Gnome, for example. People knock on it a bit BUT a large group of people swear by it for workflow.

KDE Plasma is the dream for anyone who likes to tweak settings. I used it on my laptop for a long time and it is very convenient. It also manages power and monitor settings very well. In terms of memory usage it is now similar to XFCE.

XFCE is perfect for people who don't like change. It is a slow moving DE; tried and true.

Right now I am using LXQt. Not sure why I decided to do that. It looks ok. It is fast and light. That's it's claim to fame. It can be used with different WMs which is nice.

Are there any particular DE’s you like on a laptop, because of things like power consumption and efficiency that would not come normally into consideration for a desktop?

I can't say I've ever looked into it. But, I found that KDE handled things very well. I used my laptop for full workdays, getting 11 hours out of it.

I'm a KDE guy and use it myself on my notebook, but GNOME with its multitouch gestures and polished (if a little inflexible) workflow is also an excellent fit.

Tried many, but Xfce won for me:

• great keyboard support (tiling windows, virtual desktops, etc.)
• doesn't get in the way
• compact re UI (don't like modern GNOME look with lots of whitespace)
• lightweight

An even though I use terminals a lot (neovim, git, etc.), I never stuck with tiling window managers in the end (e.g. i3). Rather I'm heavily relying on:

• virtual desktops (8 or so)
• manual window tiling via shortcuts
• tmux

XFCE minimal but good looking. You could also go for MATE or Cinnamon..

i3 and never looked back!

i3
the less I need a mouse on a laptop, the better

edit: ok, you specifically asked for a full fledged DE and not just a WM. well, I picked what I needed and with Manjaro i3 as base, I had a nice place to start

Gnome hands down has the best laptop experience. If you follow the intended workflow of using tiled windows and many workspaces. You can get to a very large number of windows, without getting lost, even with just the laptop screen.

Additionally the paradigm does translate well to a desktop for the times you are docked.

I use kde on my laptop

GNOME, despite the critiques it receives it's the most polished one and the one that gives me less problems

Tiling window managers like i3 are imho nice for laptops, since they do not waste any space and can be easily controlled via keyboard. Takes a while to get used to them, however.