I always wear solid color ties with my kilts. My suggestion would be to take your FLASHES (or kilt if the flashes don't have the color you want in the tie) to the store with you when going to buy the tie.

First choice for ME: Lovat Green (with the lovat green hose) to match the green in the kilt
Second Choice: the color of the single stripe.
Third Choice: Purple to match the purple in the kilt (if you will wear that much purple)
Fourth choice: Charcoal
Fifth Choice: Black.

Charcoal is above black b/c it's "softer" and goes better with the soft colors in the kilt. Black isn't BAD, but I think the charcoal would look better.

Also... a white shirt would be first choice, THEN a black one.