I am inclining towards HE-400, I heard it's on par with HD650 witb great bass response. If the bass quantity is not sufficient, I think I can always use EQ to boost bass. Is it not a good idea to buy headphones with a plan to rely on EQ to get the bass response you like??
I personally wouldn't buy a headphone knowing I would be EQ'ing it but that's my personal view on the subject. There are plenty of people around here who EQ their headphones but to me (unless it's a very minor EQ tweak) I want to hear the headphone how it was intended to sound. I personally have never EQ'd any of my headphones but I don't fault others for doing it, to each their own. I will add this though when I bought a pair of DT880 (250ohm) and paired them with a very bright amp, they were so bright that I considered EQ'ing them (later I got a warmer amp that made them sound much more pleasant).