Anything from Penhaligon's. Yep, I said, "anything". Some may be more casual than others but they all work well in a conservative environment.
I would also like to second the much earlier recommendation for Escada PH. I understand the longevity issues most people have as the initial kick quickly subsides . Also, there is such a drastic difference in the soft and warm drydown from the sharp and stinging topnotes that I think many peoples' noses are in some form of shock during the middle notes and perceive it as a weak fragrance. However, I am always pleased hours later to catch a whiff of the boozy, warm, cola-like scent on me. If you're one of the lucky ones, you will enjoy the men's club feel it engenders.