The 747-200 cockpit is pretty loud. I have a Telex ANR-500 that does a fine job. As I recall, it was about $300. The ear pieces don't seal around the entire ear, so cross-cockpit voice com is still easy. Since I'm an F/O, I usually fly with the left earpiece pulled back slightly. I got mine from
www.hartaviation.com. Many times they'll send them to you on "approval" and you can send them back if you're not happy with the fit or function of the headset.
I've seen the Sensenheiser headsets and they're outstanding, but very pricey.