Black pepper is used to season just about everything, and white pepper is used a lot in France. White pepper is also used in dishes where you don't want to see the black specks. There are quite a few different forms of salt. The main one we use is iodized salt, which is because we live in the Midwest and the government decided we need more iron. Kosher, pickling rock and sea salt all have slightly different tastes and are easier to see when put on food.
Salt enhances the natural flavors in most dishes, even pies and cakes.
Salt is also said to be better if it is fresh ground. There is really no substitute for fresh garlic. It has an intense flavor and is one of my favorite spices to use in cooking. A substance called garlic salt is on the market, but it is nothing more than bad salt mixed with powdered garlic. It is a really bad product, and I would not recommend using it.