black tie suit
The most versatile piece of clothing would be a deep navy suit. Paired with a vest, buttonhole flower and a grey tie, it's perfect for the wedding, a black tie makes it perfect for the funeral ceremony while a bow-tie is all you need to look great at a formal party. Loose the vest to make it look professional. This kind of suit is both practical and very elegant. (foto: zaremba-krawiec.pl)
Christoph Waltz was the best dressed guy at the Oscars this year. A midnight blue shawl collar (in a proper midnight blue - it's a shade or two darker than what Daniel Day-Lewis wore). Minor nits - I'd have gone with onyx studs instead of white, tucked in the pocket flaps. Of course a white pocket square, and the sleeves should be shortened a touch. But this illustrates that these are minor details when the fit is fundamentally correct. Bonus points for a real bow tie.