I've always used Winamp as my audio player.
MS Media Player 7 too bulky and complicated and Real Sux!
While its good they are always trying to make the program (Winamp) better, it already seems just about perfect to me! Never crashes (cant say that about M$), not resource hungry, easy to use yet powerful, supports all the audio formats you'd want as has great skins and plugins available for it!
Keep up the great work Nullsoft!