I think a tight black sweater directly on the skin is one of the sexiest things a man can wear. Specially with white jeans. Pair them up with loafers or nice leather lace up shoes.
I am not so keen on the black shirt, white pants duo, as it reminds me of Travolta in "Saturday Night Fever". I like white pants with light colored and tailored shirts: pink, yellow, blue.
You live in Australia, so I believe that you do not have harsh winters. In the US people are afraid to wear white after label day, restricting it to summer days. I never understood that: I love the look of white pants with a black overcoat. I never respect that rule myself. But you have to be able to pull it off. All it takes is personality and you can look very stylish in white in any weather.