I used to have the Bose QC15s but found them much too bulky. I prefer to travel light.

I now use the much more portable Sennheiser CX 880 Noise-Isolating earbuds. They sound fantastic, isolating noise really well. Currently about $89 - the best bang for your buck imo. My only complaint is that the cable gets tangled up quite often.

Sennheiser are great German quality though so I'm sure the MM450s are pretty good.