The Kodachrome $100, due out next year, is going to have an embedded strip with holographic images that appear to move when the note is tilted. Sounds like it ought to be pretty nifty....
That's how the BEP packages them. Some banks break them down into smaller batches, though, especially where higher denominations are concerned.
As a novelty I think they (polymers) are interesting and they sure do look/feel different. Have not cared so much to use them in China and Mexico! The countries that make them can probably do more in terms of colors and effects. But - when you compare them to some of the older US and Foreign designs, I like the way the ink looks on cotton paper better! I understand the security issues but that does not change my perception of what money should be like. They are notes and I like the notes to look, feel, and smell like "Good Old American Cash"! Even with the new funky color $5's - they look/feel/ and smell like money. It's sad to think that might go away soon!