My first courier bike (in Melbourne, Oz) was a bright pink Hillman MTB... had to 'age' it a bit with some black gaffer tape (to 'hide' it from too much unwanted interest), but otherwise it looked great.
I'd thoroughly recommend pink, just as long as it's really bright (T-Mobile shade or brighter)... pastel shades wouldn't have quite the same impact.
Mombee.