Replying to Good Noise Cancelling Headphones

I work at my local cemetary mowing and weed whacking all day and we are required to wear ear protection. I've been using my standard iPod headphones and just wearing them under the ear protection. However, its getting really annoying and hurts my ears after a couple hours of use.  I'm looking for a pair of around the ear (not on the ear) headphones that can block out the noise of a commercial lawn mower and can be used with an iPod. Ill be using these headphones next year in college too. Any suggestions? Im tryin not to spend more than $60. So Boise (sp?) are out of the question. Any ever use the Sony noise canceling head phones? any input would help. Thanks.