Features you'd want in a bash backup script?

[tchen]

Like this ?

http://www.lowendguide.com/3/backup/basic-website-and-database-backups-with-duplicity/

I prefer encrypting the backups.  Call me weird.  I wrote an alternative if you don't have access to trusted-backup-server.org 

http://vpsboard.com/topic/2422-how-to-do-encrypted-backups-with-duplyduplicity/

As for writing your own backup script, instead of just emailing the logs, how about some sort of syslog friendly (logger) spew.  The one thing I don't like about duplicity/duply is having to parse a horribly organic-human-readable stdout/stderr.