There are a few pretty great backup apps for Android, but our favourite has to be Titanium Backup. It requires a rooted phone, but you can backup and restore apps from Dropbox, run automatic batch backups, and even uninstall crapware.
By the way, should you want to learn how to use Titanium Backup, we've got a guide for that.
- Back up and restore any app and its settings, including protected and system apps
- Restores Market links, so the Market will continue updating restored apps
- Background batch backup and advanced batch restore
- Automatic batch backup on nearly any schedule you want
- Move apps to and from the SD card, along with their data
- Desktop widgets
- Ability to remove orphan app data
- App uninstaller, perfect for getting rid of manufacturer-installed bloatware (app freezer available in pro version)
- Multiple backups per app (Pro only)
- Backup encryption (Pro only)
- Multi-user support for some apps, like games, with a widget for quick switching (Pro only)
- Migrate some system data, like SMS and MMS, across incompatible ROMs (Pro only)
- Full support for paid apps that can otherwise only be installed through the Market (Pro only)
- Synchronise some or all backups to Dropbox and restore directly from Dropbox (Pro only)
- Many more features listed on the home page
Titanium can backup just about anything -- apps, app data, and even SMS and MMS data, and attempt to restore it to a new phone or new ROM. It doesn't always work, but I'm continually shocked at how much of my data it can restore to new, completely different ROMs or phones. You have tons of control over your backups, with the ability to set complicated schedules, back up different kinds of data on different schedules, and even back up directly to your Dropbox.
Titanium Backup is more than just a great backup app, too -- it's like a swiss army knife for Android phones. With the ability to remove crapware, move apps to and from the SD card, and the ability to delete data left over from old apps, it's really a must-have for any rooted Android user. If you only pay for one app from the Market, make it Titanium.
Titanium, while powerful, isn't the prettiest app, and can be a little confusing to use at first. Some of the backup options aren't always clear as to what exactly they do. If you're just trying to run basic backups, it isn't so bad, but if you have very specific preferences, you might need to play around with a little bit before you get it to work exactly how you want to.
The only real competition to Titanium is MyBackup. Like Titanium, it has a free and a pro version, which can perform many (but not all) of the same tasks. The big advantage to MyBackup is that it doesn't require root, so if you don't want to root your phone, it's your only choice for backup. Note that many of the features that make both apps so cool require root, so the non-rooted version isn't nearly as powerful -- but it'll get some of the job done. If you're rooted, you'll have to download the root version. MyBackup isn't nearly as popular as Titanium, but it's probably just about as good, and if you aren't rooted, it's a must-have (though rooting is a pretty easy process these days).
It's also worth mentioning that if you're rooted, nandroid backups are great -- and you can perform them easily with ROM Manager or through your recovery mode. It isn't the same as Titanium and MyBackup, though. Titanium and MyBackup will back up your apps, settings, and other data, which is great for migrating to a new ROM or to a new phone. Nandroid backups basically "clone" your system -- if you restore from a nandroid backup, everything will be exactly as it was when you backed up, including the ROM itself. This is better for backing up in case your phone crashes, you mess something up and can't boot it, or flash a new ROM that you don't like. Both kinds of backups are essential to Android tweakers, but they perform very different functions.
Lifehacker's App Directory is a new and growing directory of recommendations for the best applications and tools in a number of given categories.