Personally, I have a hard time with Good Friday services for some of the same reasons I struggle with some Advent services: I don't care for the way the prophetic texts are applied/interpreted. One of my very favorite services is the Festival of Nine Lessons and Carols, broadcast every Christmas Eve on BBC Radio from the Chapel of King's College. It's absolutely beautiful. But it grates on me that the prophetic texts are interpreted as being relevant to the birth of Christ. I have the same qualms about certain elements of Good Friday services.
But the biggest difficulty Good Friday poses for me is how to find meaning in this holy day outside the context of the doctrine of substitutionary atonement, which I don't believe in. Most people, however, do believe in this idea. Or at least they say they do. And from that flows a whole system of what I consider unsatisfying theology. Dissent from that idea and you'll quickly find yourself on the outside of almost any church or religious community. One of the best books I've ever read on this subject is Saved From Sacrifice: A Theology of the Cross. The author, Rev. Dr. S. Mark Heim, is a professor at Andover-Newton School of Theology, a joint American Baptist/UCC seminary. I strongly encourage you to read it if you consider yourself a believing Christian but you have qualms about prevailing views of atonement.
A lot of church people point out that you'd have no Easter Sunday without Good Friday. Yet, for a number of practical and emotional reasons, most people skip Good Friday observances. Every year, millions of people crowd into churches on Easter having given no thought to Jesus' crucifixion a few days before. This includes not just twice-a-year churchgoers, but also a significant number of people who think of themselves as very mature Christians. Personally, I think they would do well to immerse themselves more fully in the liturgy, music, and ritual of Good Friday observances.
In Catholicism, it is a fast day, but not a holy day of obligation. Still, Catholics fill churches and cathedrals around the world to observe Good Friday. Here's an interesting (and I would assume unauthorized) clip from a papal service at St. Peter's Basilica in Rome two years ago. I did not see His Holiness Pope Benedict XVI, but you can see the cardinals processing in and kissing the feet of Jesus. The music is Palestrina's setting of the Popule meus.
A lot of Protestant observances include the Seven Last Words of Christ (scriptural citations quoting Jesus' utterances during his crucifixion). Even in relatively "high church" traditions, the starkness of the service is meant to be arresting: no colors, no paraments, little if any musical accompaniment to hymns and solos, etc.
Here's a moving rendition of the old spiritual "Were You There When They Crucified My Lord."
A lot of art and icons present Christ alone on the cross. Of course, many of these are moving and beautiful. I also like the images that depict the others present at the crucifixion. Here is Raphael's Descent from the Cross.