Highest grossing films of 2000 tend to disagree:

• MI:2
• Gladiator
• Castaway
• What Women Want
• Dinosaur
• Jim Carey Grinch
• Meet the Parents
• The Perfect Storm
• X-Men
• What lies beneath

Given this, I would say the coolest outfits would either involve plate armor, a volleyball, or a green yak-fur suit.