If you're talking old style, the five sauces are Demi-glace,veloute, bechamel, tomato, and hollandaise. Some people would call demi-glace "brown sauce", veloute "light gravy", bechamel "white sauce", and the other 2...well, tomato and hollandaise. Some people consider cheese sauce to be the acceptable fifth sauce, but it is really a derivative. My mother never knew she was making bechamel when she made the sauce for creamed chipped beef (which my dad called SOS; PM me if you want to know the moniker) or creamed peas over salmon patties. She never knew the turkey gravy was really a veloute, or that the braising sauce and gravy for the pot roast was a demi-glace. Contemporary sauces include the jus lie, coulis, beurre blanc, compound butters, relishes, salsas, and compotes.
Some folks are of the opinion that food that is fresh and of excellent quality needs no sauce. Well, the sauce should always enhance the dish, that is certain, but my mom made the best mashed (and then changed to whipped when her hands would hurt) potatoes in town, yet the gravy she made for the potatoes made them taste even better! For noodles, you definitely need a sauce of some kind.
Chris can't have a lot of the sauces because they contain wheat in the roux; we get around it by using corn starch or arrowroot, but Escoffier is porbably tossing in his grave.
Really hot day in Idaho,
-Laura