J.I. Packer is awesome when it comes to this...check out what he thinks...
He poses this question (Knowing God Pp. 18-19),
"But wait a minute...tell me this. Is our journey really necessary? In Spurgeon's day, we know, people found theology interesting, but I find it boring. Why need anyone take time off today for the kind of study you propose? Surely a layperson, at any rate, can get on without it? After all, this is the twentieth century [Now twenty-first century], not the nineteenth!"
Further he says,
"A fair question! - but there is, I think, a convincing answer to it. The questioner clearly assumes that a study of the nature and character of God will be impractical and irrelevant for life. In fact, however, it is the most practical project anyone can engage in. Knowing about God is crucially important for the living of our lives."
"As it would be cruel to an Amazonian tribesman to fly him to London, put him down without explanation in Trafalgar Square and leave him, as one who knew nothing of English or England, to fend for himself, so we are cruel to ourselves if we try to live in this world without knowing about the God whose world it is and who runs it."
Pp. 20 He cites Five Foundational Truths of Christian's knowledge of God...
(1) God has spoken to man, the Bible is his Word, given to us to make us wise unto salvation.
(2) God is Lord and King over his world; he rules all things for his own glory, displaying his perfections in all that he does, in order that men and angels may worship and adore him.
(3) God is Savior, active in sovereign love through the Lord Jesus Christ to rescue believers from teh guilt and power of sin, to adopt them as his children and to bless them accordingly.
(4) God is triune; there are within the Godhead three persons, the Father, the Son and the Holy Spirit; and the work of salvation is one in which all three act together, the Father purposing redemption, the Son securing it and the Spirit applying it.
(5) Godliness means responding to God's revelation in trust and obedience, faith and worship, prayer and praise, submission and service. Life must be seen and lived in the light of God's Word. This, and nothing else, is true religion.
In essence these 5 foundations represent a starting point from which we are to develop our world view. This is one reason why when I join an organization, support one, or refer one I look at their Mission Statement. Mission statements are really important because they help those who are a part of an organization clearly understand why they exist, what their purpose is, and gives them a foundational starting point to develop deeper understanding of God and a starting point for clear communication of those beliefs to others.
(UPDATE 5/17/06: I listened to an interview yesterday (5/16/06) between Derek Thomas, Ligon Duncan III, and David Wells. David Wells' thesis for what Theology means in his book "No Place for Truth" is below:
1.) Confessional rooted in Scripture as divinely inspired and authoritative and relevant for all life and conduct. The truth that God has given us.
2.) Reflection/Thought life understanding of how truth has reached us through history. To think about that truth.
3.) Cultivation. Development of spirituality and moral life and practice based upon and growing out of that authoritative truth and not based upon technique and the psychological culture in which we are living today even though we receive valuable insights, but they have to justify themselves at the bar of truth.
This helps define what theology is from the "Evangelical's" perspective.