This piece probably needs no introduction.
However, a bit of a personal story. When I was about 8 or 9 I decided to play music and to take up the keyboard. I'd messed about on my dad's old harmonium and seen him playing the organ at the churches we'd been to and I was hooked. One 'easy' piece I 'learned' to play was the Trumpet Voluntary - a very poor keyboard version with chords in the left hand and the right hand playing a melody from one of those tunes made easy type books.
After dropping the keyboard at about the age of 11, in 2005 at the age of 19 I decided to take it up again. The piece that I could remember how to play still was, yup, the Trumpet Voluntary. However, I had discovered my dad's organ version and used it to learn to play the organ and also to read music better. The score was littered with chord names and notes written in with letters when I was done but I could play the organ including pedals!
This was also the piece that introduced me to virtual organs. While searching for examples of the piece played on organ to listen to, I stumbled across the site Virtually Baroque and realized that virtual organs, even in their early stages, were far superior to digital organs. The rest is history - here I am 12 years later able to play the organ moderately well, and own a large virtual organ, thanks in large part to this run of the mill wedding favourite!
Hope you enjoy.