I used just ordinary worker-protection earplugs when there was some very noisy construction work going on in my building. These were just simple shapes made from memory foam. Very cheap and very effective.
1. They are for use on airplanes.
2. They do not work. http://www.google.com/search?q=noise+canceling+headphones+%2...
The employee would flick a button after you put them on that also turned on some subwoofer that made a huge amount of grey noise.
Now sure that is somewhat airplane-ish, but that's sneaky.
Then another player introduced me to Shures. I've now owned a few sets (most currently http://tinyurl.com/8eyhck) and I would never go back.
The best way I can quantify how much better they are is to say that on a plane, with the QC2s, I would have my volume at 17 (out of 20) but with the Shures it's at 10. And the difference when considering non-ambient noise is even greater. With these in and no music, you can't hear people talking to you from the same room.
They're also significantly less bulky, and more durable. The QCs crack easily, and really require a hard case if you're traveling with them at all. I did have a pair of Shures where the earbuds separated, but they honored the warranty even though it was a year out of date and even sent me a newer, significantly more expensive model as a replacement.
On the other hand, I also had a pair fall out of my pocket, which is $400 lost in an airport.
EC530s. That little PTH dongle is nice if you find yourself often needing to switch to hearing conversations (if you're at work for instance) but I never really found it to be worth the effort.
What the QC2s have going is comfort. The high end earphones, namely the Shure and Etymotic and at the highest end, custom in-ear monitors offer superior noise isolation with sound quality comparable to the best in existence.
You can get Etymotic ER-4Ps for $174 on Amazon. They're comparable to the highest end Shure earphones. The Ety's will have less visceral bass.