I recently had my backup camera and a 35mm 1.4 lens stolen during a shoot. I currently shoot with a Nikon D7000 and the lenses I have left are 50mm 1.4, 50mm 1.8, 18-105 kit & 55-200. I can't decide if I should buy a 2.8 lens (17-50, 24-70, 70-200) or should I buy a D600. I shoot events mostly but I've been getting hired for different sports lately. Which would be the better buy?