Well, as I’m sure you already know, the conventional wisdom used to be that one’s first two suits should be solid navy and charcoal. That's probably still good advice, although these days, in the U.S. at least, I think you might substitute a mid-gray for the charcoal, or make it a third suit.
That’s probably the most anyone can say at this point. "Appropriate" isn't a property an item of apparel has on its own; it describes a relation between the garment and a social context.
EDIT: @archibaldleach just saw your post - thanks to you too for the solid advice!