I have a pair of DT990-Pro 250ohm headphones. I love them but it feels like I'm running them right on the edge of their capabilities. I often have to turn the volume down to avoid over-excursion of the headphone drivers. I use a Yamaha C-80 Stereo Preamp from 1984 as a headphone amp and it has a VERY powerful headphone amplifier, such that all of my little-dot units were almost immediately retired when I got it. Now my C-80 works these DT990's like a $5 whore.
The only headphone I ever had that had as much bass as I like is my Sony XB700's, but other than the bass, they sound like crap in the rest of the spectrum compared to the DT990's.