Try WinVibe 2007. I have it and it sounds the best so far out of WMP, HTC AM, MortPlayer and GS Player. Best part... it's free.
Link here:
http://www.freewareppc.com/multimedia/winvibe.shtml
Extra skins here:
http://winvibe.tistory.com/category/Skins
The visualizations are terrific and it is LOUD. Has many functions too.
"For users with QVGA and 400MHz/higher, please download this software
here."