i've tried it, and it works for me
ac3 (raw from dvd) with Valex ac3-decoder (winamp-plugin)
standard wave and ogg with xmplay itself
mp4 (with FAAC 1.24.1) with the native plugin or the winamp-plugin (the winamp one works perfectly, the native one seems to remap the channels or forget one, cause i don't hear anything on surround right)
wma with xmp-wma, but that one seems not to support more than 2 channels
.
at least no freezing here