I feel like re-submitting my nominee from last time...
"The Marshall Tucker Band" - The Marshall Tucker Band.
As one of the "Big 3", the Marshall Tucker Band completed the formula which equated to "Southern Rock". Lynyrd Skynyrd was primarily hard rock, the Allman Brothers were primarily blues rock, and the Marshall Tucker Band was primarily country rock. Their debut album had everything a country rock band needed to create beautiful music. These qualities are still found today in the country rock bands that play our nations bars, state fairs, and regional stages. Combining the beauties of the electric guitar with the acoustic guitar and adding a pedal steel guitar, some flute activity, a little fiddle, and some piano work, and you have one of the greatest combinations in Southern Rock.
This album also finds the world being introduced to probably the greatest guitarist in Southern Rock history, Toy Caldwell. Toy Caldwell can make an electric guitar sing as well as the guitar legends found in 70's hard rock.
This album features many classic hits from the Marshall Tucker Band like "Take the Highway", "Ramblin'", and the Toy Caldwell masterpiece "Can't You See". The re-release of this album also finds a 12 1/2 minute live recording of "Everyday, I Have the Blues". Toy Caldwell has never sounded quite as good as he does when he's jamming on his guitar for over 12 minutes on this song.
The Marshall Tucker Band has sustained for over 30 years in the music industry, and the way was paved with this debut album. I recommend this album to any Southern or Country Rock fan out there.