Something really wonderful happens when you listen to a great acoustic version of a song you enjoy. Maybe it's the intimacy of it all. Post up some your favs - modern or old, doesn't matter what genre 
I'll kiskstart it with a couple
Colin Hay - Down Under (chillingly good, one of my favourites)
http://www.youtube.com/watch?v=owAPNHiRXOg
Brent Smith - Devour (I reckon this guy is one to watch improve over time)
http://www.youtube.com/watch?v=X75YOn4_aLY
I'll kiskstart it with a couple
Colin Hay - Down Under (chillingly good, one of my favourites)
http://www.youtube.com/watch?v=owAPNHiRXOg
Brent Smith - Devour (I reckon this guy is one to watch improve over time)
http://www.youtube.com/watch?v=X75YOn4_aLY