[spandexninja]

Quote:

Do you have any preference between open or closed back headphones?

I don't have any particular preference, but if I had to chose I would chose open back.
 
I prefer on-ear better because I find it uncomfortable to have so much material constantly touching the (oily) skin around my ears. 
 
I'm considering getting the Koss KSC75, Koss Portapro or Sennheiser PX100-ii rather than the HD25-1 ii because they're cheaper and apparently more comfortable. How big of a difference in sound is there between the 3 lower end headphones and the HD25-1?
 
 

 

[kmw1]

The HD25-1 II do have better clarity and much deeper bass then any of those headphones. A similar headphone to those is the V-MODA Crossfade M-80 - I haven't yet had the chance to test them and they have mixed reviews in terms of comfort.
 
If comfort is priority, then you can't go wrong with the PortaPro, but we're all different, so you may prefer the others. I find the KSC75 sound slightly brighter than the PortaPro, which are warmer sounding. The PortaPro have a ComfortZone setting which helps alleviate any kind of pressure on your ears, the only slight negative is hair can sometimes be trapped in the headband when taking them off. The KSC75 clips tend to dig in to the back of my ears and can be a pain to put on. I've never heard the PX100, but apparently they're more forward sounding. I've used the PortaPro's for the last 5 years whilst working from home, up until last year, when I decided to upgrade all of my equipment.

 

[tomperrino]

the denon series should be the right choice for you,
 
 

 

[Sweden]

It seems no one is adressing the question on finding the most comfortable on-ear headphone.
My opinion under 300: B&W P5 and Bose QuietComfort 3(not sure about American prices..). Under 50: Sennheiser PX100. Don't think it's possible to beat the PX100 for a on ear design in terms of comfort. This thing can be worn for a whole day without you even noticing it! 
The ultimate in comfort I have found in Sony MDR CD2000 and Sennheiser HD-555. I don't have a massive head or large ears so I'm not sure how this would translate for a person of those features.