Archangel is an archiver for 2005 and beyond. Some features are:

+ cross-platform
+ individually {compressed,bzip2ed,gzipped} entries
+ individually {signed,encrypted,signed+encrypted} entries
+ entries can be padded to arbitrary lengths

All in all, a combination of zip, tar, and gpg on steroids

You can now backup files, and not be worried about people reading them,
either in transit or at their destination.

Entries have a maximum size of 1 MB (by default) internally, so that
media problems mean that you can recover the parts that aren't affected.