As a software developer and photographer I've always had large amounts of data that had to be backed up. I started with CD's and DVD's (long ago) but the disadvantage is that the write speeds are low (data is less reliable when written at high speeds), they cannot contain large amounts of data, they have a limited life time (max 5 years), and last but not least they require much room because they are stored in boxes.
So, now I'm using small removable USB disk drives (500 GB or more). I have three of them. One is always connected to my PC to sync files at the end of each day. The other two are identical and contain a complete copy of all my data directories. They are updated once a week alternately. One of them is located at my home, the other is stored at a remote location. They are swapped once a week after the update.
Because USB disk drives are mechanical devices you must be careful not to drop them. Each of my drives is stored in a lunch-box, wrapped in bubble-plastic. In the box is also the USB cable and a piece of paper on which I note the dates of the updates.
I have already done this for several years and I'm still happy with it because you can store a lot of data in a small space in a reliable way.