Time Machine is a good "starter" backup solution. What I mean is when backing up redundancy is a VERY VERY good thing. I would recommend getting 2 external HD's, one for Time Machine and the second use to create a bootable clone using either SuperDuper or Carbon Copy Cloner. The reason having 2 backups is wise is backups fail too!!! You also don't want to put 2 methods of backup on 1 external HD. The reason being is when (note I didn't say if) the EHD crashes you will have lost all of your backup, this is a very bad thing. Also TM is useful for recovering lost files however you cannot boot from Time Machine. However with a bootable clone you can boot from it.
With any computer (Windows, Mac, etc...) you should ALWAYS have a sound backup plan, if you don't when your HD crashes (don't say it hasn't happened to you yet, if it hasn't you've only been lucky!!!!) you can restore all your valuable information such as photos, music, movies, financial data etc.... Working without a backup plan, well it's just plain stupid.