Best Way to Play Music

I was wondering what is the best way to play your own music collection (MP3s, WAVs, any other ones?) through the sound system. Apart from XM, FM and the CD player, the choices are (unless I forgot something):

1. Bluetooth phone
2. Phone thru USB port
3. Flash drive thru USB port
4. HDD (from copied CDs)
5. Stereo input jack

Please rate these according to Best Sound Quality, Convenience (easiest to play your music collection) and Features (shows album art, song and album titles). What do you all think gives you the best overall experience? I definitely lean towards better sound quality, but convenience and features are important to me as well. What are your thoughts, Hobson?