The Five Kingdoms.

Kingdom Methods of Nutrition Organization Environmental Significance Examples
Monera

(in the broadest sense, including organisms usually placed in the Domain Archaea).
 Photosynthesis, chemosynthesis, decomposer, parasitic.
 Single-celled, filament, or colony of cells; all prokaryotic.
 Monerans play various roles in almost all food chains, including producer, consumer, and decomposer.

Cyanobacteria are important oxygen producers.

Many Monerans also produce nitrogen, vitamins, antibiotics, and are important components in human and animal intestines.
 Bacteria (E. coli), cyanobacteria (Oscillatoria), methanogens, and thermacidophiles.

Protista
 Photosynthesis, absorbs food from environment, or trap/engulf smaller organisms.
 Single-celled, filamentous, colonial, and multicelled; all eukaryotic.
 Important producers in ocean/pond food chain.

Source of food in some human cultures.

Phytoplankton component that is one of the major producers of oxygen
 Plankton (both phytoplankton and zooplankton), algae (kelp, diatoms, dinoflagellates), and Protozoa (Amoeba, Paramecium).

Fungi
 Absorb food from a host or from their environment.

All heterotrophic.
 Single-celled, filamentous, to multicelled; all eukaryotic.
 Decomposer, parasite, and consumer.

Produce antibiotics, help make bread and alcohol.

Crop parasites (Dutch elm disease, Karnal Bunt, Corn Smut, etc.).
  Mushrooms (Agarics campestris, the commercial mushroom), molds, mildews, rusts and smuts (plant parasites), yeasts (Saccharomyces cerevisae, the brewer's yeast).

Plantae
 Almost all photosynthetic, although a few parasitic plants are known.
 All multicelled, photosynthetic, autotrophs...
 Food source, medicines and drugs, dyes, building material, fuel.
Producer in most food chains. Angiosperms (oaks, tulips, cacti), gymnosperms (pines, spuce, fir), mosses, ferns, liverworts, horsetails (Equisetum, the scouring rush)

Animalia
 All heterotrophic.
 Multicelled heterotrophs capable of movement at some stage during their life history (even couch potatoes).
 Consumer level in most food chains (herbivores, carnivores, omnivores).
Food source, beasts of burden and transportation, recreation, and companionship.
 Sponges, worms, molluscs, insects, starfish, mammals, amphibians, fish, birds, reptiles, and dinosaurs, and people.

Monera, the most primitive kingdom, contain living organisms remarkably similar to ancient fossils. Organisms in this group lack membrane-bound organelles associated with higher forms of life. Such organisms are known as prokaryotes. Bacteria (technically the Eubacteria) and blue-green bacteria (sometimes called blue-green algae, or cyanobacteria) are the major forms of life in this kingdom. The most primitive group, the archaebacteria, are today restricted to marginal habitats such as hot springs or areas of low oxygen concentration.
Protista were the first of the eukaryotic kingdoms, these organisms and all others have membrane-bound organelles, which allow for compartmentalization and dedication of specific areas for specific functions. The chief importance of Protista is their role as a stem group for the remaining Kingdoms: Plants, Animals, and Fungi. Major groups within the Protista include the algae, euglenoids, ciliates, protozoa, and flagellates.
Fungi are almost entirely multicellular (with yeast, Saccharomyces cerviseae, being a prominent unicellular fungus), heterotrophic (deriving their energy from another organism, whether alive or dead), and usually having some cells with two nuclei (multinucleate, as opposed to the more common one, or uninucleate) per cell. Ecologically this kingdom is important (along with certain bacteria) as decomposers and recyclers of nutrients. Economically, the Fungi provide us with food (mushrooms; Bleu cheese/Roquefort cheese; baking and brewing), antibiotics (the first of the wonder drugs, penicillin, was isolated from a fungus Penicillium), and crop parasites (doing several billion dollars per year of damage).
Plantae include multicelled organisms that are all autotrophic (capable of making their own food by the process of photosynthesis, the conversion of sunlight energy into chemical energy). Ecologically, this kingdom is generally (along with photosynthetic organisms in Monera and Protista) termed the producers, and rest at the base of all food webs. A food web is an ecological concept to trace energy flow through an ecosystem. Economically, this kingdom is unparalleled, with agriculture providing billions of dollars to the economy (as well as the foundation of "civilization"). Food, building materials, paper, drugs (both legal and illegal), and roses, are plants or plant-derived products.
Animalia consists entirely of multicellular heterotrophs that are all capable (at some point during their life history) of mobility. Ecologically, this kingdom occupies the level of consumers, which can be subdivided into herbivore (eaters of plants) and carnivores (eaters of other animals). Humans, along with some other organisms, are omnivores (capable of functioning as herbivores or carnivores). Economically, animals provide meat, hides, beasts of burden, pleasure (pets), transportation, and scents (as used in some perfumes).