On Backing Up Files

I recently checked my files especially the digital kits for my digital scrapbooking and realized that my hard drive is almost full! I know I can't just let go of everything on this computer, thus I need an external hard drive to keep all my important and precious files. Not to mention the Grey's Anatomy and Heroes series which were in my hard drive. I just hope I'd be able to convince Hubby to squeeze his into our budget. After all, these files are important too right!?