Yes, the AKG240S is indeed an excellent choise, and this one keeps getting back in other articles as well:
http://www.soundonsound.com/sos/dec03/articles/mixingheadphones.htmThis is a great article if you're interested in using headphones in the mixing studio (which is my case, since I mostly work in the studio after the kids have gone to bed...)
To my surprice, I've found the Sennheiser HD600 to be a very good choice. I've got the predecessor (HD580) which is almost as good. Though, to my feeling, this headphone is lacking to much at the low end.
But, as you read in the article, mixing on headphones is indeed much different as using speakers... so perhaps I allready own a very good headphone...
Still, the AKG240S seems to be a very strong candidate, so currently this one is on top of my shortlist...
Moon