The WSJ had a good article over the weekend on the three piece suit, and I think the author’s advice on how to wear them is sound. I would go a step further though and suggest considering a waistcoat with lapels, which add an extra bit of elegance to the overall V shape around the tie and shirt collar.
Like a suit jacket, there are different types to choose from (a few of which can be seen on Ede & Ravenscroft’s online store). An example of a notch lapel vest and matching jacket:
Engineered Garments has some excellent shawl collar waistcoats as part of their seasonal collections as well and are great for more casual looks:
I should also point out that the WSJ forgot someone.