Murray - at the risk of inspiring the wrath of the vendors here, DON'T spend $400 on a sporran. If you can get a nice-looking one of reasonable quality from Pakistan, Madagascar or New Jersey for a good price, do it.

I've never owned one of those officer's sgians dubh, but they look very cool. Not sure I'd wear it with formal attire. The handles are brown wood, right? I think you'd want a black handle with a jewel for wedding wear. There are inexpensive ones that look just fine. Hell, a vendor sent me one for free, once, when I bought a belt. I wouldn't brag about its quality to knife afficionados, but it looks just fine in my sock.

Matt has it right, though - much of this is personal choice. Listen to what all of us say, then adopt the advice that feels right for you.