Heat olive oil in a large nonstick skillet over medium-high heat. Add onion, and sauté for 4 minutes or until tender. Add garlic, and sauté for 1 minute. Add sun-dried tomatoes, sugar, 1/4 teaspoon salt, 1/4 teaspoon black pepper, plum tomatoes, and diced tomatoes. Reduce heat to medium, and cook for 20 minutes or until liquid almost evaporates, stirring frequently.
While tomato mixture cooks, prepare pasta according to package directions, omitting salt and fat. Drain; return pasta to pan. Stir in tomato mixture, cheese, and parsley. Garnish with freshly ground black pepper and basil sprigs, if desired.