We've had a lot of luck with recipes from Ina Garten, and this one is no exception. The cucumber flavor really stands out in this tzatziki and is perfectly complimented by the other ingredients.
6 oz greek yogurt
1 medium cucumber, seeded and finely chopped
2 T sour cream
1 T lemon juice
2 tsp white wine vinegar
minced fresh dill, to taste
minced garlic, to taste
1 tsp salt
pinch black pepper
1) Mix all ingredients in small bowl; add more garlic/dill/salt/pepper/lemon juice to taste.
2) Refrigerate for 1-2 hours prior to serving.