Human's best friend
A dog can live approximately 8 - 15 years, depending on the breed.
Your choice of a lifetime friend is usually determined by your lifestyle, age and family commitments.
There are many different breeds of dogs ranging in size from teacup size Yorkshire Terriers to the massive St Bernard, each with their own characteristics and requirements.
Perhaps the best way to start choosing which breed is best for you is to really examine your lifestyle, do you have (or plan to have) children, other pets, work full or part time, live in a flat, have a garden, to name but a few factors. From this you should be able to match your lifestyle commitments to the right breed for you.