Brining is an essential step in the preparation of a quality fowl - save for duck, the storebought variety being excessively fatty and thinly covered in meat. Please note that some of the "name brand" turkeys are already brined if they are packed in salt/liquid. Don't double brine.
If you are cooking a turkey to achieve the goal of having juicy breast meat and properly warmed dark meat then you must brine, rotate and tent or cover the breast during part of the cooking. The brining will prevent the loss of excessive moisture in your bird and seasons the skin, also letting the skin render its fat properly.
With a large enough bird, brining may be out of the question. Do it if you can.
Steer clear of brining recipes which are excessively long. It should not be an overwhelming "marinade," left over night, or anything like that if you are looking for a traditional holiday bird. A brining time of an hour or two is quite enough - often making a very early rise in the morning for a noon meal. Try saving time from you holiday by using mashed red potatoes, skin on, like yours truly!
I cook my dressing separately, outside the carcass for ideal cooking of the bird. A stuffed bird can have inner temperatures 30 degrees lower in the meat than an unstuffed bird, often leading to bloody dark meat and an overcooked breast.