The republican music pack it awful, some of the EU3 DLC music is also pretty grim, but the rest is fantastic, anything by Andreas Waldetoft is gold.
With that said, be aware that the Ottoman/Byzantium music DLC only plays when you play as those countries, so it's a good idea, if you like them, to open up the DLC folder and put the songs found within into your main music folder for EU3, then give them entries into songs.txt.
With that said, be aware that the Ottoman/Byzantium music DLC only plays when you play as those countries, so it's a good idea, if you like them, to open up the DLC folder and put the songs found within into your main music folder for EU3, then give them entries into songs.txt.