What Kind Of Music Should We Sing?

As you already know, I received this invitation to a local worship service this coming Sunday. In this invitation there were especially two statements (apart from the whole issue of motives and general irreverence of the invitation) that bothered me. The first statement was "music written this century".
Now, that is not necessarily a bad statement in and of itself. There is nothing wrong with music written in the past one hundred years. I assume when they say 'century' they mean the past one hundred years and not just 2001-present. I may be wrong. Regardless the case, the same will apply. While there are many songs that I enjoy written in the past one hundred years (many of Fanny Crosby's hymns, songs recorded by Steve Green, Steve Camp, Glad, etc., and many 'praise and worship' choruses), I do have a problem restricting myself to only music from the past century. And while there is much to be commended in contemporary music, there is also much to be wary of.
Let's consider just these two concerns briefly.

First, We should not restrict our worship to only 'new' music. This type of restriction is indicative of a much larger problem in Christianity today. A blatant disregard for the past is evident and Church History and tradition is being supplanted in many churches by a desire for 'relevance' or 'Seeker Sensitivity' . Churches that do not evidence this shift are labeled fundamentalist or even out of touch. And these are meant in a derogatory sense, in case you were wondering.
But is it really a healthy thing to seek to be relevant? Let me answer this in two ways:
1) Yes. The Gospel of Jesus Christ is relevant to all. The good news of the Kingdom is to be preached everywhere. The atonement of Christ is relevant to every person in every epoch. We all have the same basic problem. We are sinners. We all have the same solution to our problem. The Cross of Christ. So in one sense, we are to seek to be relevant in the most fundamental of cases.
2) No. If by relevant we mean adapting to the world's latest fads, tailoring our worship to meet the world's 'felt' needs, and making the Gospel 'contemporary'. Put very succinctly, we have an Ancient Faith. This faith has for it's God the Ancient of Days, it's Holy Scripture was revealed to the ancient prophets and then more perfectly through the Seed of the ancients, and it's veracity has been demonstrated from ancient times to the present. There is besides all of that two thousand years of Church History that we cannot ignore. In the course of those two thousand years Apologies were written, songs were sung, sermons were preached, the faithful were martyred, and the Scriptures were studied. There is nothing of any value that is 'new' that has not been written, sung, preached, condemned, or understood before. We owe our existence to God's providence in history to keep this Ancient Faith pure. We are the heirs of the Ancient Faith. When we disregard our past, we disregard our Faith and our God.
So, now ask me if I want to limit myself to only the music from this past century. Do I really want to leave the great hymns that have stood the test of time?
O Sacred Head, The Love of God (Based on a Jewish poem from the year 1050 A.D. titled Haddamut), All Creatures of Our God and King, Praise to the Lord the Almighty, and more recently, Holy Holy Holy, Immortal Invisible God Only Wise, and Joy to the World.
To use a Pauline expression, God forbid! May it never be that we reject these songs as old, outdated, or a draaaag!

Secondly, although there is much that is commendable about contemporary christian music, there is also much that is wanting. For the most part there is a lack of biblical themes, solid theology, and true worship to God. If you want to know more about this, just ask Campi. (He's shy at first, but will come out of his shell sometimes and tell you what he really thinks.) :-)
The question that is on everyone's minds I'm sure is, "What does theology have to do with worship?" Everything. In fact, if your theology does not cause worship in you, it's probably bad theology and you need to get rid of it. Theology is all about God. God in perfect harmony with Himself (the Trinity), God creating, God commanding, God cursing, God promising, God sending, God redeeming, God calling, God blessing, God working and God returning. These are the songs that we will sing for eternity. Read the book of Revelation. It's true.
If there is a lack of theological content in a song then the song is not about God, and if it's not about God and His works then we must ask ourselves, "Who or what is it about?"

Let's not throw away these hymns that were born during trying times to faithful men and women just to accommodate ourselves. Sure, sing the new stuff if it's about God, but sing the old, old, story too.