That's gotta be Xfce.
It's not so lightweight that you feel like you are making a choice between footprint and function, but not so heavyweight that it's a slug on old hardware.
It has a nice collection of tools for File Management and Terminal activities.
It is rock stable and doesn't change all that often.
It is easy to customize because it has enough drag and drop capability.
Distros like Manjaro and MX-Linux use it as default, and polish it to quite beautiful appearances.
Certain parts of it - like XFWM4 Window Manager - can be used as part of even lighter DEs like LXQt.
It's arguably nobody's first choice for a desktop, but everybody's second choice.
When I installed Arch Linux for the first time, it was the first desktop environment I wanted to install.
I would guess that everyone who uses Linux, has run Xfce at one time or other. It's the "good enough", Swiss Knife DE.

Nice

Once upon a time, I would've said LXDE.

While everything Ray said about XFCE is true, LXDE does the same but with less resource UX.  But I don't think using a desktop built on a deprecated toolkit is a good idea.  So I'd say that LXQT is the Goldilocks, IMO.  Although, in all fairness to Ray's list of criteria, it's still being developed at a fairly rapid pace and may change too frequently compared to XFCE.

Except for a new minor issues, which (hopefully) may still get resolved at some point, LXQT is my goldilocks DE.  Perhaps it boils down to personal preferences of toolkits.  If you're a fan of Gnome, XFCE; if you're a fan of QT, LXQT.

Good thread....no flames!  LOL!

I think LXQt is great and it is my DE of choice with Arch Linux. However, I am still most familiar with Xfce - I have used it since 2008 when I installed Vector Linux on an old 1998 laptop.
I know that Eric uses Xfce with Slackware so that should count for something.  :)

Well, as most everyone knows, I've been running Xfce since KDE went to v4.x (with all the funky graphics and pecans or almonds on the screen corner, the MASSIVE RAM usage, etc.).

Sadly, the newer version of Xfce has "features" (one in particular) that will probably prevent me from upgrading to Slackware 15 for a while.

Quote from: V.T. Eric Layton on December 06, 2021, 06:22:06 PM
Well, as most everyone knows, I've been running Xfce since KDE went to v4.x (with all the funky graphics and pecans or almonds on the screen corner, the MASSIVE RAM usage, etc.).

Sadly, the newer version of Xfce has "features" (one in particular) that will probably prevent me from upgrading to Slackware 15 for a while.

In all fairness to KDE, modern versions have really reduced their footprint, nearly on par with lighterweight DEs, like XFCE.  FWIW...  Although, I have no idea what version may be available in Slackware!  But might be worth looking into if you liked it, once upon a time.  KDE used to be a resource hog, but I've been very impressed with devs ability to slim it down.  It's not "lightweight", but it's better than Gnome usage and starting to approach XFCE.

Last time I checked, I was using KaOS, a dedicated KDE distro on Arch base.  KDE hovered around 350-375MB RAM at idle from a cold boot.  Xubuntu (my only point of comparison) was in the low 300s, but can't remember exactly.  FWIW...

Nice to know Hedon. I liked KDE back in the 3.x days but I've been using tiling environments so long that its hard to get used to having to click around ;)

It looks like KDE 4.14.x in Slackware 14.2 and KDE 5.23.x in Current (15, eventually).

I actually install KDE partially when installing Slackware; however, not the desktop, just the apps and libs necessary to run them; for example, K3b or Konqueror.

If I do decide to upgrade to 15, I may have to take a look at KDE if I find that I can't workaround that Xfce issues.