Sarah--what a great dress! Is the concert indoors or out? Would you feelwarmin tights--or OK? I think either would be fine--but you don't want to be too cold or too warm!
As for earrings, personally I favour dangly. Something with a touch of sparkle? Like simple hoops? Will you wear your hair up or down? If up--then small studs and a necklace.
I wouldn't do dangly earrings and a necklace--that would be too much, I think.
As for footwear--will you be standing or sitting?
How does a pair of combat boots sound?