Mine is Strawberry since it has a ton of options and plays a ton of formats. It's also (distant) fork of Amarok 1.4 and integrates well with KDE Plasma. I'm curious what other people are using these days. What's your favorite player?
I have been bouncing between CLI/GUI and several there of. On the CLI side I'm flipping back and forth between cmus and musikcube. I prefer cmus as it seems faster and has vim key motions an commands, but I like the TUI of musikcube better, its just got soo much extra stuff I don't use. I'd love to find a rust rewrite of it that trimmed out the web-server and most of the plugins as I never use them (and yes all you suckless heads I know, I could edit source and rebuild it but... Ain't nobody got time for that).
Another point for these is being able to detach them, both work fine in detached sessions so I can start an album or playlist and just say that's it, back to work. I use Zellij but I imagine using tmux or whatever would work just as well.
Now as for graphical apps I tend to use Amberol or Rhythmbox depending on what I'm doing, honestly both go fairly unused most the time. But I like having options, Amberol is more geared towards playlist style music so mixtapes or albums not shuffle all. Whereas Rhythmbox will let me just click my library and go ... both have good integrations to the widget stack in gnome and cinnamon as well as bars like nwg panel and Waybar.
Ooh had a fun though and tested. Musikcube works better in tty mode. So I will sometimes open second users in tty mode with ctrl+alt+f(1-5) or even clone a session into tty mode. and i just checked and cmus doesn't draw the whole screen only whats highlighted. so if you have to drop back to shell or something musikcube is the better option... although i imagine if you're in that situation music players and such are not high on the priority list :/ .