If you want to reduce your risk of strokes, shunning soda, both regular and diet, appears to be a wise move. In the first large study to evaluate the relationship between soda consumption and stroke risk, researchers determined that relative to study subjects that did not drink soda, those consuming a single serving of regular or diet soda daily increased their stroke-risk by 16% percent. Additionally, the researchers found that substituting either a serving of regular or decaf coffee for a serving of soda reduced stroke risk by 9-10% (American Journal of Clinical Nutrition 2012; 95).
Keep in mind that past studies have linked soda consumption with weight gain, high blood pressure, gout, heart disease, diabetes, and abnormal blood fats. In fact, I do not know of any quicker means to trash your health on the dietary front than by consuming sugary beverages.