Here is my personal best of. Obviously depends on your own taste but i'll just list the most accessible stuff they have. Still i never think festivals are the best place to see bands but that's personal opinion.
from Funeral
Neighbourhood #1 (Tunnels)
Neighbourhood #2 (laika)
Neighbourhood #3 (Power Out)
Wake Up
Rebellion (lies)
From Neon Bible
Black Mirror
Keep the Car Running
Black Wave/Bad Vibrations
The Well and the Lighthouse
No Cars Go.
I've left out great stuff i just wanted to try and get the ones that would be imediate. From the new album i'm not willing to say yet as i havent really got it in my head, song names etc. However i think at this point its easily the most accessible album. You should youtube them live, they recently did a gig that was live on youtube. If you could get a look at that it would show you why they are one of the best bands in the world.