Aperture, Shutter Speed and ISO oh my!!

A large maximum aperture is a good thing. It allows more light to reach the image sensor, and so allows you to use a faster shutter speed. A faster shutter speed freezes action and negates the effect of camera shake, resulting in pictures that are not blurred.
Another advantage of a large maximum aperture is to provide a shallow depth of field. This allows the background to blur nicely thus isolating your subject (especially effective when taking portraits).
A small minimum aperture is also a good thing. It allows you to use a slow shutter speed on a bright sunny day. A slow shutter speed allows you to depict motion.
Another advantage of a small minimum aperture is to increase the depth-of-field. An increased depth-of-field allows you to take landscape pictures where as much of the picture in the foreground and reaching all the way to the background (usually, 'infinity') is in sharp focus.