The most popular types of men's jeans are usually classic straight-leg, slim-fit, and skinny jeans. These styles offer a timeless, versatile look that can be dressed up or down for any occasion. Additionally, bootcut and tapered jeans remain popular choices among men who prefer a more relaxed or contemporary fit. Ultimately, the most popular type of men's jeans will depend on personal style, body type, and fashion trends at any given time.