To rinse or not to rinse, this is the question. It will depend on the type of rice you bought and where it's from. The process of making "white" rice is taking the hull or husk off of "brown" rice. The hull contains all the rice bran and vitamins, the good stuff. There are many non-rinse white rices out there. They have had the lost minerals and vitamins sprayed on the rice grains. So to wash this type of rice is washing away some of the nutritional value.
Some other rices, especially those from outside US, say Jasmine rice from Thailand, Basmati rice from India, need to be washed very throughly, as to clean the rice. This means bugs, dust, dirt, and rocks are some of the things that can get inside the bag. This will also make the rice less sticky when cooked. The washing also rinses away the extra starch.
Traditionally Japanese rice, needed to be rinsed and washed to remove the talc powder used for anti-caking. Japan tends to be very hot and humid in summer, and adding powder to the hulled rice made it last longer and not stick together. So washing the rice in cold water and then rubbing the grains in your hands would remove the starch and the talc powder.
Generally one would rinse till the water ran mostly clear. Then it was put in a strainer and let to dry out and then put into the rice cooker with water and let to rest for 10-20 minutes. Fancy rice cookers have a timer for this reason.