I recently saw a post from my co-worker Kushal Das: tools-i-use-daily and I thought it would be fun to share the same information:
Operating System
I use Fedora rawhide on my laptop, which is my primary client machine. I don't have a desk and desktop and monitors, just the laptop and a comfy chair. At home I have two dell CS24 servers (one is a test instance and has all my test instances for Fedora maintainers on it, the other is my 'production' server and is the firewall and hosts the primary server vm that handles all my email and other services for scrye.com). I have various small arm devices, some of which are on and some of which are off at any given time.
Desktop
Since I run rawhide and update and reboot often (usually 1x a day during the week), I usually switch off between Xfce and Gnome / Fedora Workstation. I do admit Gnome has been growing on me over time and I might give it the edge these days, but Xfce is like an old friend that I can easily also do all my work in. I did play around some with sway (wayland based i3 clone) over the break, but it seemed like it would be too much work to build up a config that would be fully usable.
Mail
I still use a pretty crazy mail setup, but it keeps working so I don't replace it. Mail comes into my main server (using postfix/sqlgrey/spamassassin, etc) then goes to UUCP over vpn (openvpn) tcp to my laptop. Then, on the laptop I use claws-mail to read the email which is locally delivered by postfix. You may think I am completely crazy to use UUCP, but it really fits this use case nicely: I can compose and send emails on my laptop even if I don't have any internet, they will simply queue and send the next time I connect. Emails wait for my laptop/vpn and then deliver. I can set larger emails to smaller priority so I get the smaller ones sooner. It resumes just fine. It handles slow links just fine. I keep meaning to just switch to imap, but it ends up not really being enough win for me to care. :)
Editor
vim all the way. I used to be a xemacs/emacs user, but I haven't touched either in years. vim is just so nice and quick and works everywhere there's no contest.
Browser
firefox now. I was using midori full time, but upstream has really not had much time of late and things have gotten pretty dire. I did move the Fedora packages to webkit2 (via an unreleased upstream branch), but many things still don't work right there. I would love to go back, but it would need some real releases and people working on it.
IRC
hexchat. Anyone out there still using xchat really should switch. I have a znc server on my main server at home I connect to.
Blog
wordpress. It's just easy and works. Sure it has security issues from time to time, but as long as you keep updated you are usually in pretty good shape. I use the Fedora packages and they tend to do well at keeping up to date.
Misc
Just a few misc items: I use pass all the time (password-safe), it has most of my passwords in it. ssh, tmux, task (taskwarriror) and ansible are also things I use all the time.