First Aid Kit, live at Public Assembly (free!)
They played a cappella, the played with a drummer, they played without a drummer, the played without mics, they played with mics, and they play superbly. Don't believe me? (I mean, you do, because I'm not a liar and we're best friends, but just play along with the setup). Here's a bit of proof via the Fleet Foxes cover:
My first video for the blog! Happy, happy.
As well as a Fever Ray ditty:
(Sorry about the snippets; I was running low on memory and wasn't sure how much she (the camera) could handle.)
I rest my case. They're lovely and glow like angels.