This will provide you with a backup that is somewhat permanent but also smaller in capacity. You can create an album of your lesson plans (Best of….) or put presentations onto DVD’s (which hold 4.7 or 8.5 GB of data as opposed to 700/800 MB of data for CDs). Now, while that may seem like a lot, if you’re looking to back up your photos or videos, you might find yourself out of space without blinking. Flash drives are great and very portable but we’ve all seen students who have lost their data because the memory has become somewhat loosened from the USB connection thanks to repeated use or mishandling. Oh, and they get lost but they are a very valuable backup method.
Again, you can organize your files in your own way to copy them over but you need to be especially careful that you copy your files onto the CD, etc. (hold down the Option key to copy the files) rather than just make a shortcut to the files which will result in you not having actually backed up at all. Make sure there is the green plus rather than a small curved arrow to ensure that you're copying! If you don’t already know how to burn a CD or DVD with your Mac, you can check out Apple’s support article at http://support.apple.com/kb/HT1152