I always found the call to prayer haunting and beautiful. My friends used to talk about "that horrible screeching" and grimace, but when I was in the control room by myself doing homework and playing some godawful failure-pop record on the air, I would sometimes grab the cart for Azan and cue it up on the monitor, where nobody but me could hear it, and I'd imagine myself in a dusty souk somewhere, hearing one of God's faithful pouring out his tortured and impassionate plea.
It's interesting to me how different cultures and different religions seem to express themselves the most movingly. The beauty that I see in Islam, when I see it, lies within the expression of so much genuine passion leaking through the boundaries of so much tortuous ritual. When you hear the muezzin wailed, it sounds so very heartfelt. You (or at least I) hear all the pain of it, all the stricture of adhering to hard ritual in a hard world, and yet so much impassioned feeling crying out around it.
By contrast, the more a Christian hymn or gospel song talks about the laws of the faith or God's rules or anything else to do with law and restraint, the less joy I can hear in it. It seems to me that within the Christian faith, the more authoritarian it becomes, the less passion is allowed to remain - that while Islam emphasizes the passion and the heart of its followers through tortuous constraint, Christianity simply stifles and oppresses more with the more it tries to control. The Christian music that moves me is that which is the least concerned with hidebound restraint; the sort that seems to care not in the slightest about what you have done or who you should be, but simply expresses a carefree barefoot joy; a transport of forgiveness that someone has felt, and feels that they've gotten simply because the world is an innately good place after all.
If you'd like, feel free to listen to these examples, and see if you hear the same things that I do. (If it matters, I myself am a rather agnostic flavor of atheist.)
Carl Story and his Rambling Mountaineers - I Saw the Light (MP3, 3.4MB)
Azan, a call to prayer (RealAudio, 387K - go here and download RealAlternative if you need a spyware-free RealAudio player)