The Buddha said that such a creator god would be either evil, indifferent, or incompetent. I can't find the Buddha's quote right now, but it's on dhammawiki.com.
As sort of a proxy to theistic belief, many Mahayana Buddhists pray to Buddhas and Bodhisattvas, while many Theravadins pray to Brahma, Indra, etc.
Regardless of whether gods or Buddhist deities are real beings, what do you think of the comfort and sense of purpose to life that praying to these deities provides to people? Does it do more good than harm?
As a Mahayana Buddhist, I believe in Dharmakaya, which is sort of a compassionate cosmic principle (not a creator god or personal god), which ultimately leads all beings to enlightenment. The concept of Dharmakaya was originally inspired by the historical Buddha:
Many Mahayana Buddhists believe that Dharmakaya is within all things, and that our own Buddha-nature is a manifestation or expression of Dharmakaya, similar to the Hindu teaching that Atman is Brahman.Even before the Buddha's parinirvāṇa, the term Dhammakāya was current. Dhammakāya literally means Truth body.
In the Pāli Canon the Buddha tells Vasettha that the Tathāgata (the Buddha) was Dhammakāya, the 'Truth-body' or the 'Embodiment of Truth', as well as Dhammabhuta, 'Truth-become', 'One who has become Truth' 
The Buddha is equated with the Dhamma:
... and the Buddha comforts him, "Enough, Vakkali. Why do you want to see this filthy body? Whoever sees the Dhamma sees me; whoever sees me sees the Dhamma."
Also, the Lotus Sutra presents the Buddha as, after his parinirvana, remaining active in the world out of compassion for us all, as some sort of cosmic or spiritual being. Are there Theravadins who believe this too?
Buddhism might offer something better than theistic belief, the law of karma.
Instead of petitioning an external being to solve our problems, we can instead take personal responsibility for the present life and for subsequent lives, by changing our thoughts and actions here and now.
The good we do will come back around to us as good, and the evil we do will come back around as evil, either in the present or in subsequent lives.
If you want to express a devotional attitude, you can cultivate karmic merit in Buddhism by making offerings and prostrations to the Buddha:
Instead of praying for other people, you can instead dedicate acts of merit to their behalf:Acts performed for the acquisition of merit (e.g., offerings made in the name of the Buddha) calculated to provide a basis for achieving Nibbana, release from the cycle of becoming (samsara); such acts of merit are, at the same time, expected to offer semi-temporal rewards of comfort and happiness here and in the heavenly worlds in future lives. These supplementary forms of religious activity have arisen out of a natural need to augment the more austere way followed by the world-renouncing disciples...
Almost all the religious activities that have a ceremonial and a ritualistic significance are regarded as acts for the acquisition of merit (Sinh.: pinkama, from Pali: punnakamma, Sanskrit: punyakarma). In this sense, all the religious activities of lay Buddhism can be explained as being oriented towards that end. Accordingly, the first two types of rituals basically have a merit-generating character and thereby receive religious sanction. For instance, the idea of acquisition of merit through a religious act and its transference to the deities and soliciting their help has the scriptural sanction of the Maha-parinibbana Sutta itself (D.ii,88-89). Here the Buddha says that wise men, when residing in a particular area, first offer alms to religious recluses and then transfer the merits to the deities of the area, who help them in return. This seems to indicate the early beginning of adoring vatthu-devata or local deities in Buddhism.
Merit (Pali: punna: Sinh.: pin) earned by the performance of a wholesome act is regarded as a sure way of obtaining a better life in the future. The performance of these is also a means of expiation in the sense that the meritorious deeds have the effect of countering and hindering the operation of unwholesome kamma previously acquired and inherited. Thus the range of merit is very wide.
For the ordinary householder, Nibbana is a goal to be achieved through a gradual process of evolution extending over many lives, and therefore until he achieves that sublime state at some future date he continues to perform these acts in order to lead a happy life. All merit-generating rituals are performed mainly with this end in view.
http://www.accesstoinsight.org/lib/auth ... el402.html
This merit-sharing ceremony, according to the Tirokuddha Sutta, was introduced by the Buddha himself in order to help King Bimbisara of Magadha in sharing merits with his deceased relatives who had been reborn among the spirits who subsist on the offerings of others.
http://www.buddhanet.net/e-learning/his ... tion05.htm
Other scholars have pointed out that the doctrine of the transfer of merit can be found early in the Theravāda tradition, and that the doctrine is in fact sanctioned by the early suttas. Then there also scholars who propose that, although the transfer of merit did not exist as such in early Buddhism, early doctrines did form a basis for it, the transfer of merit being an "inherent consequence" (Bechert) of these early doctrines.