Sorry, I've heard it for myself (and on a 200W top of the line McIntosh amp) and all this MOAR power thing for the HE-6s is really one of the most overblown urban myths around Head-Fi. BTW, some Pioneer SX amps can output more than enough power to blow the drivers and never leave Class A.
I agree with your HD800 and LCD-3 comments, I go back and forth depending on what music/mood I'm in. But, I think you'd like the LCD-X as they seem more up your alley.
It's not about the power baby. I wish that myth would go by by. Power is needed - but is has to be "good" power.