Looking for Very Comfortable Headphones

i think the most comfortable headphones are the hd800, though obviously way outta budget.. I'm not sure bout one for a budget of up to $100, the cheapest most comfortable headphone i know is the k701

Yes, the XB serie is very comfortable, but pads can be very hot and sweaty with time and the headband not very thick.

I've got a sensitive head (thank god for articles, or that would sound really wrong), to the point where I can only enjoy music with earbuds.

Be very careful with how you take recommendations on comfort, since it's veeeeeeeeery subjective. The AKG K 601s were supposed to be the most comfortable thing ever, but for me personally they were awful, couldn't stand em.

The only headphones I've had that I find very comfortable are my vintage DT990s, and those may have stretched quite a bit in the two decades they've been around. Even then, changing the original pads to new ones makes the comfort go away, so they're really only comfortable with the original cloth pads.

Hard to recommend phones you can only buy used, though, so I won't recommend those vintage DT990s. Just thought I'd point out that whatever people say is a comfortable pair may not be so at all for a specific person. Best to try them out in person.

I think you will like the Beyer DT235, one of the best out there when you factor in both comfort and sound. I agree with vid though, if you can you should try out some of them.

Go to a Guitar Center and try out KRK KNS 8400s. I can't recommend them to you if you want a bass-focused headphone (I personally like the bass they have but they don't emphasize it), but they are definitely very comfortable. It would be good to do that if you want to get a sense of what comfy headphones feel like. 

If all you can find is XB500s, I don't see what's wrong with that, as they are supposed to have good bass and generally receive good marks for comfort.