I've been looking for one too.

the Aeron chair is indeed awesome, but I would prefer one with a headrest.

The Humanscale Freedom chair has such a headrest, but its met mixed reviews.

Another nice one is the Ergohuman ME7ERG .

The thing is, you have to go in a place and sit on a wide variety of chairs to try them out, what may be comfortable for me may not be comfortable for you