I have the D2000 and the PRO 900 myself, and I must say, the XB500 outputs a greater quantity of bass at a lower quality level. You won't get a lot of fidelity with the XB500, but it does exactly what its marketed to be. For bassheads that place greater emphasis on bass as opposed to overall sound quality, I don't think you're going to find a better can than the XB500.
Thanks for the response. Yeah, well, it wouldn't become my "main headphone" but merely something for those moments when the need for BlurVision™ arises. Something to "play with" if you will.
How EQ:able is the XB500? I mean, how much can I EQ the bass before the headphones can't handle it anymore and starts distorting and misbehaving?