As others wrote. My recomends the headphones have to be on the first place than source with amp. I had HD800 and LCD2 for 2 month at home. I heard them only on my quality dac/amp but it is compromise do not have quality external amp. But HD800 sounds more real (well arranged vocals instruments, soundstage deep and wide, transparent...) and overal it is better headphone in almost everything. But LCD2 sounds normal and nice and although it is not as good as HD800 I would choose LCD2 because I listened them more often.
So for myself I would get LCDX with some quality dac/amp
or LCD2 with silver cables (it really help them)! and some dac and amp
or HE560 with dac/amp
In my opinion planar hp is very universal