I would definitely recommend the Beyerdynamic DT 880's, specifically the 32 ohm model. I got the 250 ohm model, which needed a properly calibrated headphone amp to get a full bass and treble response due to the high impedance. Presumably the lower impedance allows the extreme lows and highs to come through more evenly, so you shouldn't need an amp to get a proper frequency distribution.
Besides the frequency response, they are very durable and long-lasting, and they have an honest stereo field. I've had them since Dec 2013, and they still are super comfortable while allowing me to mix with utmost awareness of stereo space and frequency fullness.
As an example, here is something recent that I made using these headphones (note: you'd have to download it to hear properly clean treble frequencies since soundcloud embeds at 128 kbps), and here is something zircon made also using them.