Backing up Items in my finder

[fullfloridiancj]

I noticed, while using os lion that when I open up my finder all of the items on my computer are oranged in categories. Images, Pdf, music, movies presentations, developer and documents. I have a external hardrive connected and would like to place each category into a folder and back it up. Than delete the original from the computer. These categories do not come up the same way in spot light and I am trying to select each category to move into the hardrive. Can someone explain an easy way to do this without losing or missing any of my files.