I would say that "excellent" is commonly used in everyday speech to mean "very good". "Fantastic" is slightly stronger, perhaps meaning "very very good", but it is also fairly common, as is "wonderful" which has a very similar meaning. "Fabulous" and "terrific" are not so commonly used in everyday language. It is difficult to describe why; I think perhaps they are slightly old-fashioned. "Gorgeous" usually means "very attractive" when referring to people. It can also mean "very stylish" in relation to fashion ("a gorgeous scarf") and "very tasty" and/or "very attractive" in relation to food ("a gorgeous cake").