What about the Bose brand active noise canceling ear phones?
They have two styles, on ear and over ear. You put them on and turn them on and they make it quieter. They make it quieter than just wearing passive noise canceling muffs because they use active electronics to cancel noise that makes in past the muff part. They also are pretty good quality ear phones and have a standard stereo plug (easily adaptable to fit standard audio devices.)
So you can just use them for better than average noise protection muffs or plug them into an audio source and also get good music with much less outside noise getting in.
If you check out Sporty's Pilot Shop and similar sources you will see the aviation industry has excellent noise canceling headsets for use in high noise environments for extended wear such as flying a chopper or fixed wing recip or whatever. The first airplane to circumnavigate the globe nonstop without refueling had active noise canceling headsets for both pilots.
Sporty's has a Headset Wizard where you can specify many parameters and features and then search for models meeting your requirements. WARNING, they have some models running up around $1000 but less expensive ones also. The Bose units (not for Pilots, not the ones at Sporty's but the "home models") are Hi-Fi while the units at the pilot shop are for communicatioins and may not have good frequency response above 10,000Hz.
Sporty's Headset Search Page
Some of the pilot models have cell phone inputs and aux audio (MP3 etc. inputs) They have noise canceling boom mikes so you can talk on your cell in a noisy environment like on a tractor without having to shut down.
Pat