Short, sharp, and explosive. The crash cymbal isn't the biggest piece of a drum kit, but when hit, it's definitely the loudest. While other cymbals are meant keep a rhythmic pattern, the crash cymbal is used for dramatic accents, and to emphasize certain parts of a song.
In today's cymbal market, the range of brands and styles to choose from will give you no problems in finding a crash cymbal that's affordable, and bursting with immaculate force. When a crash cymbal is used in a song, people take notice. They act as musical exclamation points, and it's for this reason that your drum-kit should include a crash that's high in quality and capable of surviving plenty of hits.
With that in mind, you also need to remember that not all crash cymbals are crafted the same way. They come in many different styles and sizes, each with their own unique flavor.