Beyerdynamic DT-250. Flatter response than the 770, much less coloured sound, but still very pleasant to listen to.
I picked up a pair a few months back, and I’ve been double-checking my mixes on them. They’ve revealed some serious flaws in how I balance the low-end (in particular), and, as a result, my mixes have tightened way, way up.
I like the DT-770 for listening, but the 250 are just beautifully analytical and excellent for mixing.