Orgasm is the word they use for that heavenly feeling that all over the body.
Eargasm is the word to be used for those sounds you want to hear over and over until you feel oh-soo-gooood. 

Here are my top 3 picks:

Funny The Way It Is - Dave Matthews Band (1:05 - 1:10, 1:50-1:54, 3:57-4:01)

Imposible - Rivermaya (3:13 - 05:07)

The Remedy - Jason Mraz (0:00 - 0:09)

I'm not a guitar person. I'm in love with every sound of piano keys.
But that crispy sound of the guitar, GODDDAMMNIT!!