You could also try the Philips Fidelio x1
http://www.amazon.com/Philips-X1-28-Over-Ear-Headphones/dp/B00B3QD94O/ref=sr_1_1?ie=UTF8&qid=1426103608&sr=8-1&keywords=fidelio+x1
or some HiFiMan HE-400s
http://www.amazon.com/gp/offer-listing/B007ZG32I4/ref=dp_olp_used?ie=UTF8&condition=used
Thanks cmadrid! This is harder than keyboards!
HE400's are awesome if you like a lot of bass. Their comfort is very so so and a quite heavy. (~$300 new, $250 or less used) (I've listened to these)
The Fidelio X1's I haven't tried but what people say about them is that they are warm, with good bass and comfy. They would be on par or rival the HD600 (~$180 new?, not really sure I haven't looked them up in a while) The new Fidelio X2's have also been very highly reviewed. (~$250 new if I recall) (Haven't heard before)
HD600 are great neutral cans for pretty much anything, I hear they pair well the the M/M stack, it is great for critical listening. (~$250 ish new, easily $200 used) (Have heard)
HD650 (which I have) are warm, laid back, have great bass, sound awesome with tube amps, comfort at first can be an issue until they stretch out. They are very good for just enjoying music, they are considered very "musical" (~$300 new, ~$250 used)
HE400i's are probably out of your reach since on average they go for $400 used or with an open box but they are absolutely gorgeous. Great all around sound, very crisp and clear, they are also much more comfy than the original HE400. (~$400 open box or used $500 new) ( I also have these)
As for the Dt990, i would stick with the 250 ohm version seeing as it is more versatile with amps, with the 600ohm version it would be rather hard to run out of your phone, with the 250 ohm version you could still potentially run it out of a mobile device and still get some decent volume out of it. (I wouldn't pay more than like $220 new for them) (I have heard these)
Hope this helps you out flyers