since music is such a subjective thing, its impossible for someone else to tell you what sounds "the best" to you..
what I would do, is open google play music, go into the settings, make sure you are on high quality streaming, and make sure viper shows up as your equalizer.
depending on if you are setting up a wired headset, a bluetooth device, or a speaker, go to that slot in viper. Start a song in google play music, then go back to viper, and depending upon how you are listening to it, first enable viper, then go through the options one at a time, and see how different things and settings sound to you.
Play around with that for awhile, so you get a feel for the different things that Viper does, then there are a couple of really extensive Viper threads on xda, where you can get all sorts of setting, presets, and more, and try them out.
here is where the creator of the Viper Mod has his thread, and its a treasure chest of everything you could imagine for Viper..
http://forum.xda-developers.com/showthread.php?t=2191223
It takes alot of playing around and experimenting to decide how you like it best, but I've been using viper for a couple of years now, and once you get it down, and know what you like, you'll always install it first on any phone/rom you are on!