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?
Logitech Media Server, followed by strawberry, quod libet, rhythmbox
Quod libet starts to act funny with 50,000 flac collections. Rhythmbox too. LMS is still chugging at 100k and I can get it on any room in the house, across 2 clients on computers, 2 on raspberry pi and my android phone. If I want to listen to 24/96+, Strawberry can handle it all although I haven't warmed up to the interface. Volumio sucks, it's way too slow.