I would like to endorse these three incredibly useful Mac apps that have been recommended to me by 'techie' friends of mine. I'm not sure I could live without them, especially the 1Password.
Too many passwords to remember? 1Password can create strong, unique passwords for you, remember them, and restore them, all directly in your web browser.
SuperDuper makes disc recovery painless, because it makes creating a fully bootable backup painless. Its incredibly clear, friendly interface is understandable, easy to use, and SuperDuper's built-in scheduler makes it trivial to back up automatically. I prefer it to Time Machine.
iVolume improves iTunes' built-in sound level by calculating the volume perceived by the human ear for each song of your music collection.