I'd rather not spend more than $100, in fact if possible, but I've got a small crew of me and 1 maybe 2 others so whilest i hold the camera I will have the headphones on, too. Which will give me the best bang for the buck?
Also consider the ATH-M30's from Audio Technica. I have no experience with 'em but Equipment Emporium ranks them right up there with the Sony MDR-7506's, yet you can get the AT's from B&H for under $60.
I love my sony MDR-7506 more and more each day. I worn it all day yesterday, and did not have a headache in the end (very rare scenario for me), very comfortable stuff. If you go with the sennheisers, just don't mistake the HD 280S with te HD280. The "S" model is the way to go since it covers your entire ear. The other is not very good because it don't isolate very well.