Etymotics ER-6, I purchased them just before Kate and I went to France, and they got me through a cumulative 24 hours on the plane with no sound leakage or real discomfort. They ARE buds, you will be jamming them up against your skull, and moreso making a seal between the bud and your ear canal, but the sound is stupendous, it cancelled EVERY sound without having to blast my mp3 player, and if I removed it once every three hours or so, I avoided all but minor discomfort.
http://www.amazon.com/gp/product/B0007WTHLY/sr=8-1/qid=1140122680/ref=pd_bbs_1/002-2915489-5182455?%5Fencoding=UTF8
DO THAT THING!