"Hoe veel hout kan 'n marmot gooi as 'n marmot hout kon gooi?"
That is a thing of beauty. Lyrical. Brings a tear to the eye. *sniff*
OK Trev, here's one: "You da man" (I plan to use this!)
"Jy's die man!" or "Ditsem, bliksem!"
In an intimate situation, the words "Wie's jou pappa?" [Who's your daddy?] can also be used.