Cook spaghetti according to package directions; drain and keep warm.
While pasta cooks, melt butter in a large skillet over medium heat. Add shallots, garlic, and bay leaf; sauté 5 to 6 minutes. Add shrimp, and sauté 4 minutes or just until shrimp turn pink. Stir in wine, and cook, stirring occasionally, 3 minutes or until wine evaporates.
Add tomatoes to skillet, and cook 2 to 3 minutes. Stir in half-and-half and next 3 ingredients; cook, stirring occasionally, 2 minutes. Remove from heat; discard bay leaf.
Transfer spaghetti to a serving dish, and top with shrimp mixture. Garnish, if desired.