I've used this marinade a number of times. Very good.
1/4 cup soy sauce
3 tbsp. sugar (white or brown)
3 tbsp. wine vinegar
3/4 cup vegetable oil
1 tsp. fresh grated ginger (or ground)
1 tbsp. diced garlic (or 1 tsp. ground)
Whisk ingredients together and allow meat (3-4 chicken breasts or 1.5 lb steak) to marinate for at least an hour. When cooking, place some of marinade in with the chicken. Serve over rice.