Grado SR-80 or Shure SRH440?

I don't own either so I'm not going to recommend anything but...

Both cans are different in the sense that the grados are a open style headphone and the shure's are a closed style headphone. So it would probably be best to pick the cans that fit your lifestyle better. If you don't mind having other people be able to hear your music, go wtih grado but if you need to keep it quiet, at least to the people around you, go for the shures.

I'm not sure how much insulation a Grado could offer, not merely because they're open, but also because they're supra-aural. The SRH440 is circumaural (though the pads are a little shallow and narrow). Mine keeps my ears nice and toasty, but the strain relief on the jack leading into the left cup is a menace when I'm wearing my coat. It constantly threatens to catapult the cans off my head whenever I move my head the wrong way.

EDIT: We're talking extremely open. They make nice miniature speakers, though. You actually get a very mild degree of isolation just from the music playing, but you'll still hear the outside, and everybody else will hear whatever you're listening to loud and clear.

I can rattle off the usual suspects for you:

-Audio-Technica ATH-M50 (though the prices are a bit hiked at the moment)

-SRH840 (supposedly, if you know where to look, you can find one for $120)

-Sennheiser HD438/448

-Sony MDR-V6/7506

-Sony XB500/700 (if you like mondo bass, that is)

-Sennheiser HD280 Pro

Others will chime in and fill in where I missed things.

You might want to take a look at the d1100. To me they are a fun set of cans. They go for 120 on amazon right now.