So, after quickly comparing the Pro 900 to the D2000 with the three suggested tunes these are what I quickly scribbled down while listening:
Phaeleh - Afterglow
Pro 900: Very clean sounding. Bass is tamed, punchy and the Pro 900 doesn't seem to miss any details. The bass doesn't miss a beat.
D2000: Also very clean sounding. Bass is a little looser, though still very managed. Very detailed and crisp.
True Romance - dBridge
Pro 900: More authorative bass, despite a brighter sound image.
D2000: A little looser bass and little warmer picture.
James Blake - Limit To Your Love
Pro 900: Vocals seem a bit off. Not really off as in bad sounding, but gives a little unnatural picture of his voice. The bass is fast and powerful enough to handle this one with authority.
D2000: Very nice vocals. I'd vocals are better on D2000. Though it gets interesting when the bass starts in this one. I feel that the bass is the make or break on this song, and to be honest, the D2000's bass is too slow for this one - so the bass becomes like one big rumble instead of short fast bass beats. It's not really one big rumble, but close to.
The James Blake tune is the tune where it's easiest to distinguish the charasteristics of the two headphones. The Pro 900 is audibly faster and punchier with the bass while the D2000 gives a more natural picture at the expense of speed and that raw "energy" I described earlier. I have to say that the differences between these two cans are pretty minimal anyway. These differences are however what makes or breaks with certain music. Do I regret having both? No, not at all. Albeit being early and not having either really broken in (The D2000 is about a month old and I got it as a birthday gift), it is easy for me to pinpoint already the different uses these two cans have. The Pro 900 is clearly more tuned towards faster paced music, while the D2000 really shines with everything else that is a little slower. I wouldn't recommend anyone over the other, however, if you know as a fact that you listen more to bassier and faster styles like D'n'B or anything electro ending with -core - the Pro 900 will obviously be your better friend. If you listen more to hiphop or reggae och anything with a little slower pace, I think the D2000 will outshine the Pro 900 because of the more conventional sound signature and a little more "natural sound".
As for soundstage I think they are very comparable. The D2000 is a little more 2D and the Pro 900 3D - though, I wouldn't say that either is better than the other. Actually, they are comparable in any kind of situation. The main differences are that the D2000 are a bit slower and the Pro 900 more authorative.
The most natural analogy I can come to think of is someone waterskiing; the D2000 is the one skiing - riding the waves and surfing calmly after the boat. The Pro 900 is the boat.
I hope I have helped a little and I hope you take this comparison with a little grain of salt; neither are really burned in and both headphones can handle what they are served. If you go with just one of them - you'll be more than fine. None really outshines the other.
I can do these ones a little later, okay? Though, I don't think the outcome will change much..
D2000 - an allround performer
Pro 900 - does electronic music "perfectly"
Pretty new, mind-blowing and staggering information, right? 
Edited by Coq de Combat - 12/30/11 at 2:13pm