Thanks for all your help guys! I think this is my first Pro-Audio buy that I am really confident about. I went to Guitar Center today and tried out the Beyer DT 770-80, DT 880-250, Shure SRH840, and SRH940. The Beyers definitely win hands-down on the comfort front.
The 880 definitely had a more natural sound that I liked, but it definitely leaked too much outside noise in (the store was a little loud) so passed on it. It was a toss up between the SRH840 and Beyer DT 770, but the DT 770 cable wasn't my favorite - it wasn't detachable or coiled.
And with the Amazon sale on the SRH840 - I went ahead with the Shures. I figure for $130, its worth it even if I grow tired of them. They sounded nicer than I expected. I think my own bias towards them initially was totally unwarranted (everyone seemed to suggest them). Plus they were decently comfortable and had detachable cables that I liked.
Now my final question, are there Beyer Velour pads out there that will fit the Shure SRH840?