Mac OS X's Time Machine backup is the easiest and cutest backup in the industry. But for many its performance stinks, forcing people to turn it off. Why?
A great idea Few people back up their data because it's work. You have to choose what software and hardware to use, buy it, configure it and then hope it works when you need it.
Time Machine solved that. Part of Mac OS X since Leopard it automagically backs up the stuff you care about.
It's easy: plug in a 2nd disk - USB or FireWire - to your Mac and it asks if you want to use that disk for Time Machine. Click yes and you're good to go.
TM backs up hourly. It keeps hourly backups for 24 hours, daily backups for a month, and weekly backups for all previous months thereafter. But it isn't an archive because it kicks old stuff out when the disk fills up.
To restore a file click on the menu bar TM icon, choose "Enter Time Machine" and you get the nifty interface: