Joy to the world! -for all these joys are available to everyone to some degree.
Notice the music above is over two hours long... it's the entire work. Handel wrote this in only 24 days- hundreds of pages of music for choir and instruments. It was written to help the listeners understand more about Jesus Christ, the Messiah. The lyrics are taken directly from the Old and New Testament, and go through His life, from before his birth, clear through his sufferings, Atonement, resurrection, and glory. A good, short video giving some of the background can be found here, or see a fantastic blog post here. I love to feel the power of the music and the message. At one point while this music was being composed, a friend came to visit and found Handel sobbing with emotion after writing the Hallelujah chorus. Handel is quoted as saying "I did think I did see all heaven before me and the great God himself." It is customary to stand while that chorus is sung... but did you know the chorus is referring to Christ's Second Coming? The scriptures this chorus comes from are Revelations 19:6, 16, and 11:15. It, like the "Christmas" song Joy To the World (which Handel wrote the music for), are really a celebration of the future day when Christ rules as the righteous King of kings. (You can read more about the background of the custom of standing here.)
He signed the work "S.D.G": Soli Deo gloria, or "glory to God alone".
Most people claim the best-known bit, the "Hallelujah Chorus", as their favorite, but the two below are my favorites.