I would also add that as a "once in a lifetime" experience, you should try and get in the nose of a 747 (i.e., on BA). It's a very different atmosphere from, say, a 777 - much more private, calm and serene. Of course, nothing beats AA's flagship suites for comfort in and of themselves. But if you're smart about it, you can ride those on certain domestic U.S. routes pretty easily.