foobar2000.
I was just thinking about this today, that maybe the reason why some people don't use foobar is because their logo looks so unfriendly. Before I used it, I saw the logo, and it turned me off from trying it out. But then I heard positive feedback from people, and started using it, and the program works very well. But I honestly think they should re-design their logo to make it more friendly-looking. An image such as a logo plays a role in how people will perceive the program.
Anyways, foobar2000 is perfect for playlists, I can play all my music, separated by different playlists. There's even this hello kitty layout that I can pick from a list of many layouts, it's so cute.