The right waistcoat/vest

[Cygnus]

I guess that would depend on where you intend to wear it. If you're looking for formal day wear, any of the five-button waistcoats above would do (though my preference is for plain wool waistcoats rather than shiny silk/polyester). If you're looking for something to wear as evening wear (with a bow tie), I would recommend a three-button waistcoat.

Because it can be very difficult to match colours, something like these red waistcoats, maybe with a change to silver buttons, would probably be a good bet.