One of the things that non-Buddhists don't seem to get, especially if they are Christian, is what the statues are in Buddhist temples and what they mean to Buddhists. Like everyone else, Buddhists' opinions on this vary a great deal; and to the Western non-Buddhist, it doesn't help when names like Kwan-Yin or Tara are frequently denoted as "deities." These beings, are clearly not deities in the Western sense of the world; they lack unique personhood for one thing (the Buddhist view is that the "self" is a construct of the mind). In addition, in many temples there are statues of past masters as well. As a general rule of thumb, because of the prevalence of Boddhisattvas, Mahayana temples will have more statues than Theravada temples. The latter will at most have statues of the Buddha, as of course they do not have the Boddhisattva tradition.
Buddhists' use of statues probably did not begin until the Greeks invaded what is today Afghanistan; the first Buddhist statues are notably Greek-looking. The first Buddhist temples were in fact modeled on the tomb of the Buddha - the stupa that evolved into the pagoda in East Asia. This writer is no expert in ancient Western religious traditions, but if memory serves me right the religions of the Greeks and Romans had components of mythic qualities and perhaps personhood ascribed to deities like Apollo (the early statues of the Buddha taken from Transoxiana bear a resemblance to Apollo).
Many Western Buddhists, based on teachings from China and Japan, understand the statues to be representations of universal attributes of Buddha nature; and that these represenations and attributes are not separate from them. Indeed, when one looks at any statue, whatever it may be, it is perceived, and what the perceiver experiences is a confluence of whatever the statue is, how it appears based on the environment in which the statue is situated, and the overall state of the "aggregates" (form, feeling thought, volition, perceptions) of the "person" perceiving the statue.
Thus the statue for a Buddhist practicing mindfulness is a mindfulness of the representation of the form in the midst of the other aggregates of which the person is aware.
Often in Buddhist services and temples one bows or places palms together in front of a statue; this is to acknowledge the experience and accomplishment of those who have practiced the Buddha Way, and to acknowledge this capability from those who bow or place palms together. Buddhanet's FAQ says:
What about Buddhist shrines and images?
The shrine found in Buddhist homes or temples is a focal point of Buddhist observances. At the centre of the shrine, there is usually an image of the Buddha. This image may be made of a variety of materials such as marble, gold, wood or even clay. The image is a symbol that helps people to recall the qualities of the Buddha.
The shrine may also have such objects as a volume of Buddhist scriptures to represent the Dharma. Some shrines may include other items such as images, pictures or photographs of Buddhist monks and masters to represent the Sangha. When a Buddhist stands before a shrine, the objects he sees on it help him to recall the qualities that are found in the Buddha, Dharma and Sangha. This inspires him to work towards cultivating these qualities in himself.
So in this sense it is clear that these statues do not represent the exact equivalent of deities in the Western sense. It is true that there are temples in which people "ask Buddha" for various things, and whether that involved a Buddhist evolution from Hinduism or the other way around is a unresolved matter. What can be said though, is that when someone "asks the Buddha" for some favor, they are not asking something from a being that is separate from themselves; they are in effect making a request from/to their own nature. Or, from another vantage point, the Diamond Sutra says:
(1) Thus have I heard. One morning, when the Buddha was staying near Shravasti in the jeta grove of Anathapindika's estate, He and His company of twelve hundred and fifty monks went into the city to beg for their breakfast; and after they returned and finished their meal, they put away their robes and bowls and washed their feet. Then the Buddha took His seat and the others sat down before Him.
(2) From the midst of this assembly rose the Venerable Subhuti. He bared his right shoulder, knelt upon his right knee, and, pressing his palms together, bowed to the Buddha. "Lord," he said, "Tathagata! World Honored One! How wonderful it is that by Thy mercy we are protected and Instructed! Lord, when men and women announce that they desire to follow the Bodhisattva Path and ask us how they should proceed, what should we tell them?"
(3) "Good Subhuti," answered the Buddha, "whenever someone announces, 'I want to follow the Bodhisattva Path because I want to save all sentient beings; and it does not matter whether they are creatures which are formed in a womb or hatched from an egg; whether their life cycles are as observable as those of garden worms, insects and butterflies; or whether they appear as miraculously as mushrooms or gods; or whether they are capable of profound thoughts or of no thoughts at all, for I vow to lead every individual being to Nirvana; and not until they are all safely there will I reap my reward and enter Nirvana!' then, Subhuti, you should remind such a vow-taker that even if such uncountable numbers of beings were so liberated, in reality no beings would have been liberated. A Bodhisattva does not cling to the illusion of separate individuality or ego-entity or personal identification. In reality, there is no "I" who liberates and no "they" who are liberated.
So the "referants" of the statues - the beings that the statues represents - are themselves not separate from those who pay homage to the beings or make requests, in the Mahayana tradition. To me, this seems somewhat more rational and "obvious" than the way in which statues are used in Christian churches. One might ask, then why have statues at all? That answer would lead to a discussion on forms for Buddhist practice and "worship," which, as you might have guessed from the quote marks, bears no resemblence to what Christians would call "worship." But that's a subject for another post...