I love grilled Filet Mignon served medium rare with a side of horseradish sauce. I think less is more when it comes to marinating a good steak. Here are my top 4 "go-to" ingredients for marinating:
-Fresh Chopped Rosemary
-Fresh Chopped Thyme
-Lemon Juice
-Minced Garlic
Rub marinade over the steak and put in zip-loc bag and refrigerate for at least an hour. Remove from marinade and sprinkle with a little salt and pepper. Cook to your desired temp via an outdoor grill (my favorite) or when the weather is not cooperating use a grill pan inside. Although I find cleaning a grill pan after it has been used to be one of the most tedious pans to clean.....

Here is a good recipe using the above marinade that serves the steak over pasta that you should try too:
From Cooking Light
Italian-Style Grilled Steak
Serves 4
Ingredients
1 (1-pound) beef rib-eye steak, trimmed
1 tablespoon finely chopped fresh rosemary
1 tablespoon finely chopped fresh thyme
2 tablespoons fresh lemon juice
1 garlic clove, minced
1/2 teaspoon kosher salt
1/4 teaspoon freshly ground black pepper
Cooking spray
4 cups hot cooked spaghetti (about 4 ounces uncooked pasta)
4 teaspoons extravirgin olive oil
Preparation
Cut beef across grain into 1/4-inch-thick slices. Combine beef, rosemary, thyme, lemon juice, and garlic in a large zip-top plastic bag; seal. Marinate beef in refrigerator 1 hour, turning occasionally.
Prepare grill.
Remove beef from bag, discarding marinade. Sprinkle beef with salt and pepper. Place beef on grill rack coated with cooking spray; grill 1 minute on each side or until desired degree of doneness. Serve with pasta. Drizzle oil over beef and pasta.