I listen to mostly to EDM,Rock,hip/hop and indie. I would want a pretty good amount of comfort so that would be a large factor.
At this point I don't have an amp, but id be willing to spend $75 on an amp.
I cant decide between these headphones
- DT 990 pro
-ATH-AD9000
- 598's
What sources will you be plugging the headphones into?
I own the DT990 Pro 250-Ohm, ATH-A900X (closed) & HD558 headphones.
Of the three options you listed, I think I would take the ATH-AD900X (assuming ATH-AD9000 is a miss-spelling)
The AD900X is only 40-Ohms, so can work fairly well with out an amplifier, but using a decent quality (low impedance) headphone amplifier with it is a plus.
It also has better mids then the DT990.
Audio Technica ATH-AD900X, $170
http://www.ebay.com/itm/261822695208?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The HD598s are well liked, but you can get the cheaper HD558 and remove the black rubber tape from inside the cups and get them it sound somewhat more like the HD598s
The HD558 and HD598 use the same driver.
The DT990s strong bass/treble slightly overshadows the mids, but the mids are clear.
Good headphone if your looking for a "movie theater" type sound, but really has to be used with a decent headphone amplifier.
I prefer the more balanced sound of the AD900X.