It's always interesting to view a technology from a new perspective, and that's what Silver Key allowed me to do. And believe me, it's all in the perspective--Silver Key ($30, 30-day free trial) creates password-protected "parcels," which are pretty much the same type of thing as a password-protected zip, rar, 7zip or other archives The biggest difference is that Silver Key allows you to attach large binary keys to your archives as text files. The program steps you through the parcel creation process, never letting you forget that you're creating an archive that's secure.
Another very nice feature is a password/passphrase creation dialog with a spellchecker to prevent you from accidentally entering a misspelled phrase that will take you forever to recreate. The company's sales hook is that more data has been lost due to forgotten passwords than damaged media. I can't vouch for that; however, I have seen it happen enough to tell you that you shouldn't dismiss the possibility.
The company offers a free utility that simply decrypts Silver Key parcels--so if you choose to use Silver Key, recipients of your files don't need to buy it. Silver Key does a nice job of squashing files, and it worked perfectly in my tests. This program has enough going for it that it merits consideration as a super-secure alternative to the more popular archiving utilities like WinZip and WinRAR.