Any backup is better than no backup. But if you're planning to start safeguarding your data, you should do it correctly. The current typical options are:
Back up to removable media (CD, DVD, Zip Disk, Thumb Drive)
While this might work for really small amounts of data, it is not automatic (relies on human intervention). Typically, a full backup is taken each time (not just the changes). Most importantly, the data is still most likely on-site. In case of a disaster, your backups are of little to no help.
Back up to tape
Much has been written about the pitfalls of tape backups from people running into burning buildings to recover tapes that they never bothered sending off-site to stolen tapes with credit card details. Worst of all, the tape deterioration that gets discovered when you need to restore data. Tape restores are cumbersome and often require system administration intervention, even if all you want to do is something as simple as restoring a single file.
Back up to an on-site machine (backup server)
This is an improvement! As long as you have the right software, you should be able to backup automatically, incrementally and securely while still being able to restore quickly and painlessly. Remember that your data is still on-site. By not replicating your data to a remote server, you are still exposed to cases of severe risk case of natural disaster, calamity, theft or vandalism.
Back up to a remote server (online backup)
This is the safest option given your data is off-site in the event of any disaster. Usually there is a service provider to maintain and monitor your backup & restoration operations.
There are certain features you should have with a managed online backup solution to safely and effectively store, manage, maintain and access your data.
The most secure and reliable option of backing up is "Disk to Disk (D2D)".