R10 for me. 4070 was very nice, too, but comparing 4070, R10 (and the Omega II) side by side, the later production R10 is the best I've heard yet, closed or open. Unfortunately I didn't pay close attention to the 4070 due to the presence of other cans but it was very good as far as I remember. The L3000 was thrown into the mix but that headphone just sounded plain weird to me (only heard them for a minute so the impressions aren't really meaningful). Amp used was Corda Opera, Mapletree Ear+ and the headphone out from my Apogee Mini-Dac. (4 person-)meet conditions apply.
The Ultrasone 750 given some acclimatisation is pretty good for the price although not quite as good as equally priced open headphones. Certainly not neutral, especially in mid-treble, but the soundstage depth and bass (extension, linearity and impact) are pretty impressive. Excellent for pop, rnb and some eletronica. Vertical soundstage is only mediocre and the treble sounds rather unnatural compared to HD650. Not my cup of tea for classical and jazz.
CD3000, owned them twice, never did it to me due a strong metallic touch in the treble. Again, not so great for classical music.
just my 2c