I use the following:
Shure SRH440
Audio Technica ATH-M40fs
Sennheiser HD515 (open backed, so not good for recording/tracking)
 
the Senn's were by far the most comfortable.  I could wear them all day without fatigue.
 
however, I'm going to throw a bone out here and let everyone bite it off...
 
I bought some custom in-ear monitors for wearing when I play on stage connected to Avioms.  They're AWESOME!
 
they almost completely isolate you from anything else going on in the room and they are comfortable for quite a while.  not as long as the senn's but I could leave them in for a long time.

I have K702s that feel very spacious, but I don't know whether you'd consider them to be large or not (are they the same size as the K240s?)
 
-Ki
Salem Beats

Salem Beats
I have K702s that feel very spacious, but I don't know whether you'd consider them to be large or not (are they the same size as the K240s?)
 
-Ki
Salem Beats

There of a similar design and build as the K240 - they have a better driver though.
 

Beyer DT 990 Pro (open , less sound pressure, linear responsse, sound open like crazy , best in biz and not expensive ,)

I like the beyerdynamic DT 880.  They are very confortable and mellow!

+100 for beyerdynamics Dt 770

My most comfortable headphones are a set my wife bought for me that I would have probably never looked at.  Hifiman he-400.  The planar drivers sound really good too.

Beats studio wireless are extremely ear smashing... And noise cancellation hiss hurts the ears. (I will return them to Bestbuy)

Bose ear ergonomics are wonderful (quietcomfort 15 and 25) but they notoriously fall apart after a couple months.

Of course Bose and Beats have opposite bass loudness... Bose lacks warmth and Beats has too much warmth at 200-400hz.

I cannot wear Bose qc with a hood on the head because the noise canceling becomes distortion with every jogging step.

My in-ear Shure buds are fair but give a nice flat sound...the ears never really get comfy.

I will test some of Beagles's suggestions.

Thanks for this great thread!