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?
About 2 years ago, I moved my music to Jellyfin and have been using their media players on every platform I use (iOS, FireTV, Ubuntu, and Windows). At this point my music library is close to 200 GB, kinda hard to store that much on every device I own.