@mwng: My personal recommendation would be something like Sennheiser 595's. I've been using my pair for years, more or less all day every day, and they are still going strong. I think the 598's are the current version of it. The comfort is probably the most important thing to me though, I have to admit. To be able to wear them for hours on end and not have them pinch my ears or feel uncomfortable.
Edit: Should add, these are totally open headphones. No sound isolation or anything, so while I think the sound on them is pretty good (certainly better than whatever I had before), you should expect to be able to hear other people in the house or the like while wearing them. I kind of like that myself, because closed phones are the ones that tend to pinch me and get sweaty and uncomfortable more easily.