An Argyll jacket in Charcoal is probably the most versitile combination. As much as I love my lovat green tweed jacket, it is not the best for an occasion where the formal Argyll with silver buttons would not be quite appropriate -- and as Panache pointed out, the PC is for evening attire only.

So, to sum up -- a Charcoal Argyll Jacket (with waistcoat).

Cheers,

Todd