It's easy to define things and but it's substance is profound and deep and not any one can understand in the capacity in the ordinary minds of being. The enlightenment of Buddha cannot be be measured in the ordinary understanding. Buddha's wisdom is deep and profound extends as vast as the universe. In the Medicinal herbs chapter of the Lotus sutra calls the Buddha possesing such wisdom " One who knows all things(LS5,98); and emphazes the BUddha's Wisdom, which is a wisdom that embraces all species". Such Knowledge sounds a lot like the faculty of omniscience that Christians attribute to GOD. As pointed out, In Christianity the perfect wisdom of the Creator is termed omniscience. The arguments seems to go that since all things were created by the divine being, he is all-knowing as you had said.
The Buddha's encompassing knowledge is not of this kind. there are variuos interpretations, but i believe that the Buddha's knowledge of all things consist of wisdom to completely and thoroughly understand all living beings and what teachings should expounded to them;and that he posesses this wisdom because of his compassion to lead all people to happiness. The Buddha's knowledge of all things could be called " wisdom that is at one with compassion "

Tientai, a scholar, or CHIh-I(4 A.D) of China interprets " One who knows all things " as indicating one who posseses in his or her heart the three kinds of wisdom: the wisdom to understand the universal aspect of all phenomena, the wisdom to understand the individual aspects of all phenomena, the wisdom to understand both the universal and individual aspects of all phenomena as well as the Truth that permeates them.
Of these, the wisdom understand the universal aspect of all phenomena is the wisdom to percieve the truth of nonsubstantiality. It indicates the wisdom to understand that, in essence, all things are nonsubstantial and and impermanent without discrimination. This is the wisdom of voice-hearers and and pratyekabuddhas, and it is also called the wisdom of nonsubstantiality.
The wisdom to understand the individual aspects of all phenomena is the wisdom to percieve the truth of temporary existence. This is the wisdom of bodhisattvas who, based the realization that all things are essenmtially nonsubstantial, understand the diversity of individual entities the temporarily come to existence. Bodhisattvas require this wisdom because they have to lead poeople to happiness amid the realities of Life.
The wisdom to understand both the universal and individaul aspect of all phenomena is the wisdom of the Buddha, who posseses the wisdom of both the universal and individual aspects of all phenomena and can employ them at will and without error. This is the wisdom of the Middle Way, which has taught by Shakyamuni.
Belief alone might some confidence, but belief in and itself does not guarantee that what we believe is true. In order to truly undestand of Life around us, and gain genuine confidence, what we need is wisdom- penetrating insight rooted in the depths of Life itself.In addition, we need the internal power and fortitude to conquer our own weaknesses and fears, and to act confidently upon our beliefs, thus demonstrating their validity through our actions.In addition, we need the power of compassion and courage to enable others to transcend their own limitations and establish the true confidence and happiness in Life.

Unlike other religions, the belief or faith in Buddhism is not blind faith that rejects the criteria of reason or fanaticism, but faith rooted in reason. It is in fact of rational functions a procees of cultivation of wisdom that begins with a spirit of reverent searching.

The Buddha nature or the world of Buddhahood is not abstract or a mere intellect. It is, however, a process and the journey of cultivating in the truly depths of our being. The true state of of the Buddha's Life is one of endlessly seeking self improvement, in which wisdom deepens compasssion and compassion deepens wisdon. It is a process of boundlessly and continously striving for perfection. The two wheels of that will to perfection which carry it along on its eternal journey, are faith and understanding.(Please read my article on Purpose of Religion)