If you happen to hail from Scotland you may want to wear a kilt. Whilst the kilt part of the ensemble remains the same, the jacket/waistcoat comes in two flavours:
1. the Bonnie Prince Charlie jacket and waistcoat which is actually an evening outfit but is commonly worn through the day for special occasions
2. an Argyle jacket and waistcoat which is rather less fancy.
You would normally wear a bow tie with the Bonnie Prince Charlie outfit and a normal tie or cravat with the Argyle. The choice is yours.
The waistcoat that usually accompanies a Bonnie Prince Charlie jacket is cut low as befits an evening waistcoat but there is also a vogue for a three button waistcoat to accompany the Prince Charlie jacket which looks better with a cravat or normal tie.
As for which tartan, you need to research your family roots if you want to have an answer to the inevitable question on the day, "What clan is your tartan?" but if you cannot truly find any Scottish ancestry, then don't worry; most gentleman's outfitters can provide a good list of non-clan tartans such a Flower of Scotland which you can wear without impunity!
For those who are Irish or Welsh there are also tartans which you can wear with accompanying jackets. For the Welsh, quite often the jackets are vivid green or red so do check with your other half before arranging or it might be a very short day!
