The tie bar is the accessory that both literally and aesthetically brings an outfit together. The tie bar or tie clip should only be silver color. End of story. Any other color appears too experimental to have the effect that the silver tie clip has. It might seem a bit traditionalist to advocate for a single color in an accessory, but a silver tie clip has so many advantages over other colors that any other color is useless compared to it. The silver tie bar is simply never the wrong decision, it is basically impossible to mismatch it with any color and it will always add a debonair air to your look.
If you are using skinny ties -as you should be- it might be a little difficult to find a tie bar that fits your ties. Thetiebar.com and cufflinks.com have several options that will fit the slimmest of ties. If you are using skinny ties, adding a tie bar to your wardrobe will make your look oh so Italian. There is much to be said for the minimalistic style of Italy, but one thing that is for certain is that to have an Italian looking wardrobe is never a bad thing.