Country

There are many types of music that seem to be closed circles--like classical and opera, country music is something many people aren't exposed to in youth. There are always a few pieces in every genre that someone could enjoy, so here are some potentials to try if country is new to you:

Turn of the century early blues:
C.W. Stoneking - The love me or die
Alison Krauss - You Will Be My Ain True Love
Vince Giordano and the Nighthawks - Georgia on my mind

Classic, very folk style:
Dolly Parton - Jolene
Lindsey Buckingham - Big love
Rachael Yamagata - Jesus was a crossmaker

Light road trip/driving music country style:
Gloriana - Wild at Heart
Little Big Town - Boondocks 

Miranda Lambert - Down

Miranda Lambert - Famous in a small town

Old style/twangy and propulsive:

Miranda Lambert - Texas as hell

Miranda Lambert - Gunpowder and lead

Slow choir:

Salt Lake Vocal Artists - Dixie [slow and a capella; excellent example]

Pop/cheery style:

Florida Georgia Line - Cruise

Lauren Alaina - Georgia Peaches

Lauren Alaina - One of those boys

Jason Aldean - She's country