Often called Prince of Wales thanks to the Duke of Windsor's affinity for it, glen plaid is a great pick if you've already got a closetful of solid-color suits. Its black-and-white base gets along well with varying stripes and patterns. This Hugo Boss virgin wool three-piece makes a big impact in the office or at a wedding – and thanks to the vest, you'll look like a million euros, even if you ditch the jacket.

Plaid peak-lapel suit, $1,695; shirt, $195; and tie, $95, all by Boss; silk pocket square by Ralph Lauren Purple Label, $125