You could do a vertical piece. I have attached a photo of buffet I did for one of my client's Dining Room. I added wall sconces, however, if you don't want to get into electrical you could add wall brackets with vases of plates on them, or candle sconces. It is your Dining area and candle light is a nice warm light for entertaining, or dinner just the two of you.

You want what you put above to have the total width of 3/4 of that buffet.

So either one art piece of 3/4 the width, or two things whose width pus the separation between the two add up to that.

You can use a fantastic starburst mirror, or a piece of art work.

You don't want to clutter up the buffet with several small things.

Skip the blue and white ware unless it is really quality.

Candlesticks, or flowers in a vase, or a flowering plant, or a tea set on a tray would all look great.