Couscous comes in an instant variety as well as a kind that needs to steam. Wheat processed into flour will be discussed further on in Cooking 101's Basics of Baking, scheduled for April 22. Short and medium sizes have rounded shapes and are stickier, better for picking up with chopsticks, starchier for puddings. Long-grain rice is more dry and cooks to a fluffier consistency, making it good for salads and pilafs. Basmati rice is a fragrant, nutty long grain.
Glutinous rice is sweet, sticky, short grained, and it's used widely in Asia.
Brown rice must be refrigerated because it can go rancid. It takes longer to cook than other rice, but it is more nutritious. Experiment with the different kinds to see what you like. For starters, buy some white long-grain rice and learn to cook it correctly. Now, you have mastered another basic cooking milestone.