Anthony Green
Backseat Goodbye
Bright Eyes
Caroline Smith
Dear And The Headlights
Elliott Smith
Go Big Casino
Lydia
M. Ward
My Little Pony
nevershoutnever!
Seabear
She & Him
Taxi Taxi!
The Spill Canvas (early stuff)
This Is Ivy League
Some might not be always fully acoustic - but hey, they're all good. ;]
Also, if you find some acoustic versions of All Time Low, This Providence, Motion City Soundtrack or The Starting Line songs grab them, because they sound marvelous acoustic.