Pretty quilt. Very dramatic. I would maintain the drama by repeating the black, but not as the first border.
I would go for either the tiger fabric or a match to one of the darker blues in the blocks for the first stopper, maybe a1" border, then a small black border, maybe the same size as the strips and then one of the prints you have in the blocks as a larger, probably at least double or triple the size of the black border.
Audition the borders, by laying the fabric next to the blocks in the size that you think you want to do and take pictures. Let us see what you are thinking. Taking the pictures will give you a reality view of what the final product will look like. It's like looking through one of the door viewers that people recommend you get to preview fabrics. Think hotel or motel....