You don't want to turn on Disk Encryption unless your boss makes your! Something goes wrong, (and where here fixing things going wrong) then EVERYTHING is gone.
If you have files you want protected, which we all do. The best way is to set up an Encrypted Disk Image, then when you want to access those you mount the image, use the files then eject it when you're finished. Very secure, easy to use, and if somethings gone wrong you can just trash that Image.