1. hd650-with a good amp these are a talented performer. With a great amp, they are just down right talented. Uber comfortable. Exceptional fit and finish if you're okay with plenty of plastic. Incredibly musical with most material. You could buy these and a good amp and call it end game...well, I know that I could.
Weakness-still looking
2. Maddogs-I think somewhat of a darkhorse around here. Earning a reputation for a deliciously smooth orthodynamic sound. The signature is cohesive across the spectrum with a touch of warmth around the bottom end. Fantastic isolation and has a rugged tank like build. Scales about as well as the hd650.
Weakness-some may consider the slight darkness a con...I don't.
3. he400-despite taking some deserved heat for production issues, this is a beautiful headphone. The second best bass that I've ever heard. Only second to the lcd2r2. This is not flabby exaggerated or boomy bass. It is rich with texture and impact. Great with Jazz, Pop and anything with a nice bass-line. Very good sound stage and a good all rounder.
Weakness-heaviest and least comfortable of the three.