There was a post in the official wow forums about the windows media player trick. IIRC it had to do the OS prioritizing things differently. If I can find the post I will link it up.
Wow forum post
Personally I have reduced the paging file size on my gaming machine(8gb ram) to 1gb. I tried to run without a paging file and there was tons of memory creep. My available ram would slowly shrink to less than 1 gb. When I enable the small page file, this stopped occuring. I guess the OS needs to write some addressing info to the page file, and if the page file isn't there maybe it writes it to physical ram?