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?
MPD + Cantata
For the most part I just lump all my music into one playlist regardless of album or genre, but day to day I also use several different computers, and I find MPD to be the best for syncing configurations across all of them. Cantata also allows me to see album artwork and track information really easily and has good touchscreen support compared to terminal-based MPD clients.