Linux

Kubuntu or KDE Neon 100%

Ultimately they both use the KDE Plasma desktop environment, which is the only DE I've ever seen that has a proper modern look by default (others IMO look like either the 2000's or an OS 4 Kidz), as well as being pretty featurful for multi monitor productivity

Arch+KDE Plasma is what I personally am gonna switch to this summer

I've been preferring KDE lately tbh. Very flexible and familiar. Still don't know what that activity thing is for though lol

Linux Mint Cinnamon. Stable, yet tons of customizations possible and makes the jump from Windows a whole lot easier (I jumped 1.5 years ago and will never look back).

I use KDE Plasma on RebornOS (an arch spin).

It thoroughly depends on how much you're willing to configure

I think right now EWW + hyprland is the new hotness, if you're willing to edit text files and scripts

If not, go KDE if you like windows, gnome if you like mac.

For some reason I find stock GNOME UIs appealing

You can use most desktop environments on most distros.

If a distro has its own GUI and it doesn't exist on other distros, usually that means either it isn't free software or it's not good enough that anyone has bothered to package it for other distros.

I run tiny core linux for the UI personally

Fedora with Gnome

Fedora. It ships vanilla GNOME which is just a very pleasant experience. Vanilla GNOME is just something else man.

I used the Pop Os default for a long time and just recently switched to i3 Manjaro, it’s been pretty nice once you get past the learning curve of i3

Absolutely love GNOME on Fedora. Workstations + Hotkeys are amazing. I really dig the minimalism and compartmentalisation it offers.

Distro is irrelevant. DE/WM choice is all that matters as far as GUI goes. Also, if you want a GUI that looks or feels like windows then KDE probably has you covered in that you could probably customise it to mimic windows.

I quite like the Desktop Environment in elementaryOS. I think it's called Pantheon Desktop? It's very polished. Or InstantWM from InstantOS is also interesting and has some nice animations and effects.

Personally, I use simple and minimal Openbox

Probably any distro that ships KDE Plasma 5 as default - I'm stuck with GNOME for now as I need to use Evolution for work (EWS mail accounts), but if I had the choice I'd probably be on Plasma.

The distro which comes with the best customization in my opinion is Pop!_OS. Simple, clean, straightforward and comes with the POP SHELL which basically simulates a tiling window manager

Feodora and Debian have a GNOME experience that has not been ruined to make less innovative in favor of making the UX more similar (and therefore familiar) to that of the worst desktop operating system available (windows).

If you've seen but never really used GNOME in a daily workflow it looks and feels alien. Thats becausethey devs are trying to make something that is friendly to the people who actually use it and intuitive to the people who are new to desktop computing, and they are making no attemt to appease thoes who believe that it is impossible to do better than Microsoft has with Windows.

If you've never really used it (and have used ms windows), Vanilla GNOME is alien to you. If you have really used it, nothing else is yet on its level.

i3, and swaywm , I have used almost ... All Linux/BSD/Windows/Osx/Unix Desktop Environments. I really like #enlightenment but it can be pretty buggy especially on wayland.

Distro doesn't really matter nowadays. You can get all desktop environments to work on most distros. Especially the big players like KDE, Gnome, Xfce have hundred distros they are shipped with by default. Most big distros have versions for each of the most popular desktop environments. Therefore, I would suggest that you look for the distro which fits your needs best and then install the desktop environment you want to work with afterwards, if there isn't a flavor of your distro that ships with it already.

I'm going to hop in here and suggest you try out Linux Mint. This is a distro designed for people who are coming over from Windows or Mac. It "just works". The UI doesn't throw away thrity years of convention simply to be "linux". Everything is exactly where you expect it to be and most of what you need is already installed.
Mint offers a choice of different desktop environments which are all laid out exactly the same, but have differing degrees of polish. If you're using a very old PC, you may want to choose XFCE because it is very lean, but lacks some of the nice graphical touches. Most people just use the Cinnamon desktop environment, which is highly customizable and polished.
I fully switched to Mint many years ago and never looked back.

For me, it's Fedora + KDE when I need a GUI. I used to be an AwesomeWM guy for a very long time but I needed a proper GUI for my 5 year old. I'll convert her to i3 or Awesome one day....

Just trying out OpenSuse microOS currently, as an alternative to Fedora Kinoite, and the installer doesnt even load.

I dont like Ubuntus variant of Gnome. I think GNOME can look good but its apps are often horrible. Mint has a better set of simple but powerful tools.

But I would stay with anything rocking KDE. I recommend fedora Kinoite fro ublue.it (better video previews and working RPM firefox basically), its a really great distro.

I like to use good ol' stable Debian with i3-gaps as a window manager.

You might be looking for a KDE desktop. Many of Windows's better more modern desktop features are copied from it, and KDE is very customizable out of the box without needing to install a bunch of extensions like you do with Gnome. KDE can be customized to fit many different desktop paradigms, with the default being like Windows 10.

The real question is what Window Manager has the best GUI... you can run any window manager on any distro - it just takes a little work.

If you're talking about out-of-the-box without any user customization, I'll make a couple suggestions that I think work for new Linux users - not that I'm saying you're green, but most power users know they can fully design the OS from the ground up if needed.

PopOS - In between - GNOME-like with some PopOS customizations under the hood.

ElementaryOS - MacOS-like WM thats clean fresh and easy to understand

Mint - Cinnamon DM, Windows-like with some customization possible

Currently I am using Cinnamon with Debian and quite like it. Previouly I enjoyed XFCE, espacially on slower laptops. Never really liked GNOME or KDE Plasma though. GNOME has too many animations and feels slow. At the same time its not very customizable. KDE on the other hand feels slow as well and though it is kind of fancy it seems not to be my taste and I did not like the way you customize either. That is not so important to me anymore. So please don't read from this that Cinnamon or XFCE would be great for customization. I would not know it.

Distro? Probably Debian, because it has all the desktop environments. If you want, you can have Plasma, Gnome, Xfce, Cinnamon, and MATE all installed at the same time and switch between them at will. Most distros seem focused on one specific DE, which if I'm not mistaken means switching to another involves reinstalling the whole operating system.

The big downside of Debian is that the software in it tends to be very out of date. You'll get security updates and the occasional bug fix between Debian releases, but that's about all you'll get.

You can get a rolling-release experience by running the “unstable” version, but as the name implies, upgrades will sometimes fail or break something, and you need to know your way around the system in order to recover from that. Not a problem if you want to learn to be a Linux sysadmin anyway, but if you want your system to Just Work™, then unstable Debian is unfortunately not for you. It's a trade-off, as with most things in life.

Deepin is great too. Unfortunately it is not fully translated so that you come across Chinese quite often.