Are you going to use the headphone output integrated into the Mac? If so, don't bother spending big cash, a fairly inexpensive pair of Sony MDR-7506 should do the trick.
Using them in the field, or at home in post? If the former, IMO you'll want a pair that provides good isolation, and to me that means in-ear 'phones like the Etymotic ER-x, Shure ERx or some such. I've found the ER-6 (that fit my custom molded plugs) isolate very, very well.