1) You are the kind of person that does everything on the web and may have a few pictures that are important. This can be the simplest. Have a thumb drive that you copy things to on a regular basis. Make sure you get all of your internet favorites as well.
2) You create a lot of documents and have another computer somewhere in case of emergency. This case you should consider an online backup service. For around $50 per year you can have your machine set up to automatically back up all of your documents anytime you are online. This way there is no forgetting to perform the backups. It also keeps copies of things you delete as well as multiple versions of files you change regularly.
3) Not only do you create a lot of documents you have a lot of programs loaded and you really can't be without a computer. You need a 2-step approach to backing things up. 1) Have the online backup program as described above. That way, even if the machine is stolen, you have the documents you need. 2) Have a program set up to copy EVERYTHING on your computer. In case of a hard drive failure you would be able to load everything onto another drive or a new computer and be running in hours instead of having to hand reload everything.
We can help you determine which is best for you and discuss costs. If you ever need it we also have rental machines as well.