I agree with Sidssp, the 580 and 600 are very comfortable. For me they were the most confortable and best sounding of any traditional headphone I tried. Problem was I needed isolation (580 and 600 are open-air type) so I went with the Etymotic ER-4P. You might consider the Etymotic if you have problems with traditional headphones, but be forewarned they can't really be used while you are moving due to microphonics and some people do not like anything stuck in their ear!
Gee I kinda like my Stax Pro Lambna's, cost me $700 back in '90 and still going strong, I could never go back to dynamic type headphone the electrostatic is too revealing. They are big but not uncomfortable. Stax dedicated headphone tube amp is a must.. improvement over their voltage conversion boxes. Model 007t or something like that is what I use, sounds great.
The most comfortable phones that I have are: Sony R-10, Sony CD3000, Stax Omega II, Beyerdynamics DT-880, DT-770 Pro, DT-990 Pro, Sennheiser HD-600, Audio Technica W-100. I totally agree that the AKG K-1000s put a lot of pressure on your temple, as do most Grado headphones. Other than the Sony R-10's and Stax Omega II's, all of the other cans mentioned above are reasonably priced (from under $200 to $400 range) and widely available.
Yeah....... what about the Sennheiser HD-580's or the HD-600's??? I happen to own a pair of Sennheiser HD-580's, and I have had mine for two years going now. And let me tell you, of all of the phones that I have owned in my life (mainly, the mass market shit that has came with the personal stereos that I have purchased over the last 20 years or so (and then I have also bought better phones when I have purchased my personal stereos, because the ones that always came with my portables have sucked worse than the 15 year old Hoover Vacuum Cleaner I have recently replaced)....... but I have tried out some AKGs and some Grados too...... because I wanted to buy some more serious phones for my audio system), the Sennheiser HD-580 are by far the most neutral sounding phones I have ever owned, and the most comfortable BY FAR. I was afraid that when these phones that these phones were going to be discontinued at first. But when I found out that Sennheiser is still going to continue manufacturing them, I was delighted by the revelation, as well as the price drop that has taken place at the time (from about $350.00 to about $200.00) at the time, so then, I went ahead and purchased me a pair. Don't have no regrets about doing so either.
I am thinking about either purchasing me a second pair for use with my audio system only, and continue using the pair I own now just for home theater and for portable listening.
I didn't mention that they sounded great with home theater either, did I???