Reading peoples list really show you how subjective headphone comfort is. I guess head shape, ear size and shape, sensitivity to clamp and weight do a lot to explain the disparities.
I had to think about this for a second but here is my top 5 list.
1. Well used HD555
3. Stretched out HD598
4. Well used HD600
Headphones like HD800, HD700, all kinds of Beyers, PX100, D5000/D7000, Mad Dog, 1R, K550 and I'm sure I'm missing a few here are...