Most common table salts are not good to consume because of the way they are processed. Major salt producing companies dry their salt in huge kilns with temperatures reaching up to 1200 degrees F, changing the salt's chemical structure. It is refined to remove impurities, and to make it attractive in appearance. After refining, this salt looks great, and flows easily out of your salt shaker, but most of the minerals have been removed. Additives bleach the salt whiter, prevent water absorption while the salt is in the box and make the salt flow freely in your salt shaker. All this processing prevents this salt from being properly utilized by your body. The only salt you should eat is unprocessed sea salt.

Refined salt, also called common salt, table salt, etc, is 99.9% sodium chloride. Sea salt is about 95% sodium chloride, 4% potassium chloride plus tiny amounts of about 60 other minerals. Although these come in tiny amounts, they are vital to health.

All the scientific studies showing salt to be harmful are studies using refined salt instead of natural sea salt.

Information on sodium wouldn't be complete without also including potassium -

The balance of sodium and potassium are strongly related to blood pressure. A diet high in sodium and low in potassium is the most potent dietary factor known to increase blood pressure.

A diet high in potassium can significantly lower blood pressure in people with a low potassium intake. People who are concerned about their blood pressure should eat a diet high in potassium.

Excessive consumption of sodium depletes the body’s stores of potassium. Alcohol, caffeine, and sugar deplete potassium levels in the body.

Concerning potassium, processed and refined foods are bad for three reasons:
The refining process kills potassium.
Refined carbohydrates (white flour and sugar) increase the excretion of potassium.
Refined foods increase the need for potassium because of the large amount of sodium they contain. It is very important that potassium and sodium are balanced. Usually, processed foods contain massive amounts of salt, thus increasing the need for potassium. Thankfully, potassium is in just about every natural food there is. Potassium is found in meats, dairy, fruits and vegetables. You should eat about four times more potassium than salt. For example, if you consume 1000mg of salt, you should eat 4000mg of potassium.

Potassium is well absorbed, but is not stored in large quantities in the body. When cooking vegetables, do not discard the liquid. Drink it or use it as a soup or gravy base, as much of the potassium in the vegetables has been dissolved into the liquid.

Potassium, along with sodium and chloride are electrolytes that function to maintain the normal balance and distribution of fluids throughout the body. The electrolytes are intricately related in their function and are always found in pairs. The electrolytes, including sodium and potassium, are involved in the maintenance of normal pH balance, and work in conjunction with calcium and magnesium in the maintenance of normal muscle contraction and relaxation, and nerve transmission.

The major electrolytes in your body are sodium, potassium, chloride, calcium, magnesium, bicarbonate, phosphate and sulfate.

Potassium helps to support normal muscle function, increase energy, maintains mental health and cardiovascular health. It also helps to support a healthy nervous system. Diets high in sodium are the most common cause of a dietary deficiency in potassium. However, the most common cause of potassium deficiency is caused by excessive fluid loss (sweating, diarrhea, or urination) or the use of diuretics, aspirin, laxatives, and other drugs.

Sodium Recommended Daily Allowance (RDA)
The current recommendation is to consume less than 2,400 milligrams (mg) of sodium a day. This is about 1 teaspoon of table salt per day. It includes ALL salt and sodium consumed, including sodium used in cooking and at the table.

Sodium RDA - National Research Council
The National Research Council of the National Academy of Sciences recommends an approximate daily range of 1,100 to 3,300 mg of sodium for adults.

Sodium RDA - American Heart Association
The American Heart Association recommends that for every 1,000 Calories of food consumed, the sodium intake should be 1,000 mg and should not exceed the 3,000 mg limit.

Sodium RDA vs. Average Intake
The average intake in the United States is between 4,000 and 5,000 mg of sodium per day.

Potassium RDA = 1900 to 5600 mg a day

Iodine is widely available in seafood; cod, sea bass, haddock, and perch are good sources. Kelp is the most common vegetable seafood that is a rich source of iodine. Dairy products and plants grown in soil that is rich in iodine are also good sources.

Some good salts:
Celtic Salt
Le Paludier Salt
Lima Salt
Muramoto Salt
Pacific Salt, sun dried, product of New Zealand
Redmond Real Salt from Utah

Potassium/Sodium Content of Selected Food, in Milligrams per Serving (Murray, 1996).