What style of liturgy do you like? Contemporary? Ultra-modern? Conservative? Traditional? The very question reveals a certain mindset that many Catholics today are unaware of. What it reveals is a presumption that "what we like" has a bearing in the liturgy. That, in itself, is a problem. Try to imagine, if you can, someone asking the same question of the Apostles in the first century: "most Reverend Apostle Paul, do you prefer the Mass in modern or ancient form?" Paul likely would have said, "it does not matter what I prefer, it is supposed to be for God, not us!"
I do not want to put words in the mouths of the Apostles, but we can be pretty sure that the concept of "modern vs. traditional" would not have come into their minds other than the question of Old Covenant temple versus the New Covenant Church. Down through the centuries, there were various changes that the liturgy of the Mass encountered. Some things were done away with once the Church apparently recognized they were not for the best. Other practices "morphed" into something else over time. No one imagines that the Mass was unchanged until the Council of Trent. Yet, those changes were not for the sake of "pop-tunes" or "contemporary innovations".
In all of these adjustments that took place, none of them appears to be for the purpose of "updating" the Mass; the very concept is foreign to the minds of our forefathers. Although I may have missed something, I know of no point in history (before the last century) that the Church felt it needed to "modernize" anything. There was one point when it became clear that fewer and fewer people were able to understand the Greek language so the Scriptures were then translated into Latin. This seems to be about the same time (4th century?) that we find Latin becoming the language of liturgical use as well (both, by the way, were for the purpose of helping people to understand, and not to make things more "comfortable" or "entertaining").
With that in mind, we have to be critical of the concept of "style" in and of itself. What does "style" mean after all? A technical definition would tell us that a "style" is "the way that something is done". We can acknowledge that there are essentially two "styles" of the Liturgy that have existed since at least the second century. There is the Eastern and Western style. What we are used to in most dioceses in North America is the Western "style". Visit an Eastern Catholic Church sometime and get a truly different taste of Catholicism. The idea of "style" being a distinction between the way we "used to do it" and the "new way to do it" is outside the historic understanding of this concept. This modern idea stretches us beyond the historic faith, and turns the Mass into an ever-changing practice that is always seeking to suit one's personal tastes (which also might change on a daily basis).
The greatest danger of a "modern style" of the Mass (even beyond the grossly individualistic aspect) is that it quickly becomes subject to the desires and ideas of society around (and society, modern or ancient, should never lead the Church). Think of "liturgical dance" (still completely forbidden in Catholic Church's in the United States!), "praise teams", and numerous other innovations that come from "pop culture" and not from the desire to honor God.
To be "modern" in the early Church meant that it was understandable (like in the switch from Greek to Latin) and not that it incorporated particular practices that suited personal entertainment preferences of the day. This very idea of changing personal preferences in the Mass makes the concept of "Catholic" become almost insignificant. The "Catholic" Mass implied that it was going to be the same, and appreciated by all in every country, because it was "timeless". The timeless nature of the Mass is retained if the Mass is focused on reverential worship of God; if the Mass is focused on time bound "styles" then it is no longer accessible to all the laity. This is not what it means to be Catholic.
This also touches on the idea of "options" in the Mass (which I have spoken about before) and how that leads to the sense of a "style" in the Mass. I have heard someone say to me more times than I can count "each priest does the Mass differently". This is true, but it is not good. If "each priest" does Mass differently enough where the laity notice it, then we have far too many options. Furthermore, in today's culture of gluttonous entertainment the pressure will always be there to choose the options that are the most entertaining (or worse, make up a few entertaining options). Yet, when people have been submerged in a diet of me-first philosophy, then we will expect them to want the casual and easy-going options (besides, which priest would be crazy enough to choose the more traditional options?).
It is more common than I like to admit for me to hear someone say that they willingly choose to drive to a parish (other than the one they live near to) because they like the "style of worship" that the Church has. "Style" should never be the reason, unless by "style" the person means a "reverent style" as opposed to an "irreverent style" (which is really not the proper manner to refer to a "style" of worship). The very idea of going to a parish because of the "style" of the Mass reveals a deep problem in the Church today. It reveals a competition between people's personal preferences, which inevitably ignores God's personal preferences. What would God prefer in the Mass? Does He "just want us happy"? Or does He want us to offer up a holy and reverent sacrifice? How does the idea of "style" fit in with that?