Easiest way to backup data occasionally?

Karen's replicator is small, simple, and free.

For more complex (and powerful) backups, try Acronis or Genie Backup Manager.

I just set up FreeFileSync today, it is a no-frills windows, local-based (including mapped drives), free open source software at http://sourceforge.net/projects/freefilesync/.

Working pretty well so far, with easy options, batch files you can save (and run or schedule yourself afterwards), decent feedback, silent mode, timestamp/content comparison.

It seems to lack extensive naming and versioning schemes and organisation options however, and it does not have FTP, e-mail or other enterprised-oriented methods.

For my usage, it serves as a quite functional mirroring mode, where the deleted files from your source gets deleted from the destination as well. Quite useful mode for keeping a most-current safety backup of folders that are too large for incremental backups (such as music).

If you want to make reliable backups, it is not sufficient to use this or that application. You need a backup procedure that takes measures for dealing with potential risks, such as theft and backup medium degeneration. I've made a detailed small scale backup strategy which attempts to deal with a wide range of risks while requiring a minimum of effort.