I'm using (if I find time and motivation after programming on Windows at work) Eclipse CDT.

Netbeans is my favorite, definitely. I just have to add a GTK UI configuration to make it looks nice and it make it alot better

For quick or small projects I tend to use Nano with tmux + other crap. Other times I use Atom.io

xed, make, and gcc

I use vim too on a daily basis. I'm surprised so few people here use it.

I used to work with Eclipse, but it felt heavy and getting slower with each update. At work we have a special version of micro emacs, which still is an IDE, as you can compile your C programs from it and jump into the code when having errors.
For minor changes on text files, I just use vim... but meanwhile my favorite editor is Sublime Text 3.
I've found a video tutorial online, called Perfect Workflow with Sublime Text, and that showed my how awesome Sublime Text is.
Meanwhile Atom.io might be also quite similar, or even Microsoft's Visual Code... but I still stick with Sublime Text, as I payed the license fee (imho it's totally worth it) and got so used to it, that I don't want to have any other editor again.
It lacks some features big IDEs have, but I can get along with that.

Vim for anything bash/c++/python
QtCreator for larger C++ code

I've been using Eclipse what seems like forever for every type of project I work on, mostly because I use it at work. But I recently tested IntelliJ IDEA Community Edition and I really love it. Now I own the Complete Pack Subscription from Jetbrains and use IntelliJ IDEA, CLion (cmake based C++ IDE), WebStorm (best JavaScript I ever used) and PHPStorm. The integration of all related toolchains and other external tools is just amazing. I am now trying their issue tracking system Youtrack, cause integrated issue tracking right in the IDE is also very cool.
Given, I have to pay 25 bucks a month, but these tools are totally worth it.

QtCreator for C++, VIM for everything else.

I use Geany and it is really good.

One question. Is there a way to highlight the code for python3 syntax instead of python2?

Atom for anything

Had to switch from Atom, messed up my files with old versions in some cache too many times. Too annoying, switched to Kate.

Geany is my pick if I had to pick just one IDE for everything. However, if I am forced to use Java I will pick Eclipse.

I'm using Visual Studio Code both at home and at work. *ducks*.
But seriously, it's MIT licensed and actually pretty good.

Visual Studio Code here too, in my case for web development, MS is doing actually pretty good things lately!
JetBrains Rider is my choice for C#.

I use Visual Studio Code

I use code::blocks, QtCreator and eclipse (but always an older version as they are more stable). Code::blocks is not really suitable for really large projects as the indexing grinds to a halt.

NetBeans for me, my favourite by the code I use to write (PHP and Java), but when using C I loved QT creator.

IntelliJ IDEA. There has never been better IDE for Java and I doubt there will be soon.

mainly working with emacs (plus some extension scripts)... it's still the fastest and most versatile way to write and edit code for me; especially if you also work on the documentation, configuration, scripts, ... other IDEs are too focused on a single language and totally ignore that there's a lot more than some source-code files to create and maintain a program..

sometimes using Qt-creator (mainly when doing stuff for android)....

for simple single file "projects" vim or mousepad.