The Known,
I see you're a bit hesitant about your purchase, which is going to be a serious one by all means. You shouldn't decide too quickly on a $400-500 purchase, especially when it's going to be for music producing. I'd suggest you to give yourself some time and read up some more about the cans you consider. Also, read what people have recommended on other threads on here.
Here's a good (i.e., unbiased) review of the Beats Pro from Innerfidelity:
http://www.innerfidelity.com/content/monster-beats-dr-dre-pro
Headphones for music producing got to have no tendency towards any side of the frequency spectrum. There should be no bass emphasis, no highs roll-off, etc. You should be looking for a headphone that
1) is as closest to neutral as you can afford, to get a good image of what you are producing (a basic requirement),
2) is preferably open, or semi-open, to get a spacious sound stage and avoid resonances that alter the frequency response, and to be able to wear them for long sessions (personally I find closed cans to be more fatiguing, due to the relatively narrow sound stage and more emphasized L/R separation),
3) has high impedance rate, to be able to play around with volume levels, and have higher damping factor combined with your amplifier.
Portable-use headphones can't (always) meet all these requirements, especially 2 and 3, assuming you will not invest in portable amplification (if you're limited on budget, and want to get good job done at home, you'd better leave portable amplification at this time), and that you also don't want to bother your environment.
So you need to hit somewhere in the middle. This is why I recommended the DT-1350, which is, in my experience, a very good option in your case and for your needs. These will also run very well unamped (and will be able to give you more when amped as I wrote earlier). Speaking of the price, you can get them for around $240 used and still have some left for amplification. I haven't heard the D2000, so I can only comment on the tonal balance according to the data sheet on Innerfidelity - it
looks like these have too much treble energy, and too prominent mids. Also it looks like the bass is missing some tightness, but that's just a guess. I wouldn't use these for mastering, any way.
Having said that, if your preference is more towards portable use and listening pleasure on the road, things are way difference of course, and you'll probably want a good budget portable amplification combined with a colored headphone that should increase your bass, mids or highs, for a reason that is beyond me. Also, if your music producing isn't very demanding that would definitely change the entire picture as well.