Grados are good. The SR80 is a decent middle ground between the prices of the lower end models and the sound quality of the upper end models. Bass can seem kind of thin by modern standards until you're pretty high up the model line. Comfort is really polarizing though, they fit some people's heads perfectly and are pretty agonizing for other people.
HD600 are kind of soft and dark for my tastes. You won't really miss out on anything with them, but I prefer what I guess you'd call a more literal sound. They sure are comfy though.
DT880 are good all-rounders. They don't do anything specific thing super-well but don't fall short either. Again, pretty comfortable.
Don't get too hung up on the open back / closed back distinction. Closed back headphones are good for blocking out some external noise (although not nearly as effectively as in-ears) and the form factor can help enhance bass, but most closed back designs also tend to sound kind of nasal and boxy. There are exceptional-sounding closed back headphones that aren't nasal and boxy too, of course.
Headphones are pretty much a kind of audio clothing, what fits my head might not fit yours, so take my comments on comfort as a pretty vague guideline rather than a recommendation.