I use WMP9 exclusively. I don't think Winamp sounds as good. It sounds like the signal is low. I tried turning up the gain on its built-in pre-amp, but then it sounds distorted. WMP9 with Turtle Beach's equalizer is great for me. I don't have Real Playter installed on my system, and just do without .ra files altogether.
The best MP3 player I've ever used was the AudioStation32 that came with my TB Montego II. The equalizer was excellent. Never heard PC music sound as good. Unfortunately, it didn't come with the Santa Cruz, and I don't feel like paying for it.