There are numerous species of finch, but among the most popular as pets are the zebra finch (Poephila guttata) and the society (or Bengalese) finch (Lonchura domestica). These species are hardy and relatively easy to care for, so are an excellent choice for the new owner. Some of the other finch species are more challenging to care for and are best left for more experienced finch keepers. As an example, the Lady Gouldian finch is a strikingly beautiful, brightly colored finch, but are more difficult to care for and keep successfully than zebra finches.
Zebra finches are small birds, and are active and fun to watch, and quiet when it comes to vocalization (chirps and peeps that most people find easy to tolerate). Although small, they need a fairly large cage in order to have flight room (the length of the cage is more important than the height). All finches are social and should be kept in pairs - and a male and female pair will usually breed quite readily so you may want to consider keeping only females. Some people recommend keeping either in pairs or in groups larger than 6. Of course, if keeping more than a pair, you will need a larger cage such as a flight cage or aviary. While they are social with each other they are not birds that bond strongly to people (although they do become quite tame) and are good for watching but not for handling.
In general, finches have an expected lifespan of anywhere from 5-15 years. The wide range here can probably be attributed to species differences as well as an increased understanding of their husbandry, especially diet.
Zebra finches are arguably the most popular species found in the North American pet trade. They are attractive birds, and males are easily distinguished from the females. The males have black and white bars on the throat and breast, orange cheek patches and brown on the sides of the body. Both males and females have red-orange beaks, although the male's is much brighter in hue. The above description applies to the wild type coloration; a wide variety of color mutations are now available. For excellent photos of a number of mutations see the Zebra Finches Chart on eFinch.com
Next: Cages for Zebra Finches