While most grooms choose to wear the same color suit as the groomsmen, you certainly don't have to. If you want the groom to stand out, consider switching light/dark combos. For instance all the groomsmen can wear light grey suits, and the groom can wear black. Or all the groomsmen can wear black, and the groom can wear navy. Just make sure to tie them together somehow, either with the same shirt, tie, boutonnière, or even shoe color.