This is what I have too and I find them excellent - I use them on the plane even when I'm not using the IFE if I'm trying to sleep as they do block out a decent amount of sound. Also good for trains, etc. with an iPod. My only worry is when I'm on an unfamiliar train route and I miss the announcement/stop!

Although as you say, nothing is perfect and a screaming kid (or one of my other faves, an annoying pax inanely whining on in some nasal drawl about countless egregiously dull aspects of their life/recent trip to their seatmate behind you ) won't be blocked out totally. Helps though.

Got my NC11 from Shopping The World about a year and a half ago IIRC. Never regretted it. I'm sure there has been a newer/updated/better product come out from Sony in that time though.

Phil