Firstly you need to list down your total budget ( headphones + dac/amp ). As I already told you in the PM you sent me , unless your budget can fit in a D5K along with a good source , dont get the D5K . Also the price difference overall between the D2K and D5K is quiet a lot and might not be justified if the difference is more than 10k .
I got myself a D5000s cause I got a very good deal , ohh and yeah Benny tempted me as well as helped me get one :no: . Had I paid anything more than 23-25k for it(if new) , I am not sure if I would find them to be worth the price.
Also I've wanted to tame the bass on the D5000 , get the mids a bit more forward along with a wider soundstage , so I ended up doing the Lawton mods on my pair of D5K . Here is a complete comparison of D5K vs D2K along with the impressions of the mod .
http://www.techenclave.com/audio-zone/denon-ah-d2000-vs-ah-d5000-183841.html
^ While doing this comparison , I didn't have the MX1 so right now they sound even better than the impressions in the above thread. Can proudly say one of the best sounding headphones in the world .

Ever since these came in , I've never have had the urge of upgrading even after trying out lot of other high-end models
A good source can make a lot of difference , Ive tried the Xonar DX, uDAC , uDAC II , Maverick D1 , HRT Streamer II+ , Audinst HUD MX1 and I can tell you each one of them offers more detailing than the one inferior to it . If you can afford to get a HRT Streamer II+ or Audinst HUD-MX1 , would make the experience even better .
A D2000 + Audinst HUD MX1 would be as good or better than D5000 with a entry level / inferiors source . If you can get the D5000 as well as a high-end source, nothing like it .