Chances are if you're familiar with computers, you know how important the hard drive is. The hard drive is where your computer stores all of the files and information it uses. Most refurbished MacBooks come with a pretty large hard drive already, usually at least 120 GB and up. However, certain computer functions can really chew up a lot of that space quickly, especially if you're a graphic designer, photo junkie, music lover, or film geek; hard drive space can come at a premium. Consider upgrading to a 640 GB hard drive and say goodbye to worrying about hard drive space.