A nice-looking suit is the largest part of men's professional dress. Suits in brown, gray, black or blue are all acceptable colors for a business event. Be sure to match the pants and jacket. If the jacket has stripes, the pants should also have stripes. Complimentary shades of gray can be matched but are more casual than a matched suit. A blue sports coat can be matched with khaki pants for a more casual look. Occasionally, a jacket is not required when business casual attire is recommended.