This is very much a personal choice whether you choose a mixed or purebred cat. Your local shelter is a great place to go to see the cats and kittens that are available in your area. They have both mixed and purebred cats.
You should also consider your family and lifestyle. It's important to ask yourself what sort of regular care your new cat or kitten will need. Long-haired cats such as Persian and Himalayan will need daily grooming. Do you have the time and the patience? Purebred cats can come with medical issues inherent to the breed, whereas mixed breeds tend to be hardier.
Another consideration is temperament. While a cat’s temperament can be easier to predict in a purebred cat, it’s not always a guarantee. Once you’ve decided on a kitten or cat, visit her a few times at your local shelter and try to get a good idea of her temperament. Don't rush your decision.
If you have your heart set on a pedigree kitten, take the time to do your homework on different breeds. There are more than 70 to choose from. Try the HillsPet.com Cat Breed Catalog: This is an excellent place to start and it’s easy to use.