This is a Sunday brunch with the guys or family outfit! I feel like you don't have to wear dress pant to wear a blazer with a dress shirt. Just throw on some plain, simple jeans and add on that beige blazer with a neutral color dress shirt.
Why is the three piece suit a standard for every man? Not only can the vest be used on its own but it can add depth to the suit when you wear it together. But lets not forget, when you give your jacket to a lady, you can still stay mostly warm.