In most applications there is no need to mess with pH. Most fish will adapt. The best way to set up a tank is to buy fish that fit the water in your area. pH adjustment is a subject where you will hear lots of differing views. Just make sure to check the water from the store before dumping your fish into your tank. A drastic change could really hurt them even if your tank is what they normally have in the wild.
Unless you are planning on breeding them the natural levels of pH are not that important. Even then match the store and then change them to match their origional habitat slowly.