Bearnaise sauce is wonderful with salmon.
http://www.epicurious.com/recipes/food/views/bearnaise-sauce-395049
Or mix yogurt, small spoonful of mayonnaise (trust me on that one), fresh dill, and lemon juice.
If you're looking for a basting a sauce / marinade, mix brown sugar, soy sauce and ginger together, spread it on top of the salmon, and roast.