You need to look at all the colours and really make your mind up - that's a lot of money being spent on something you might not like the colour of in the long term. Night blue looks great in the right light, but do you like it on a crappy overcast day (we get a lot of those)?
Not a fan of the white, not because it looks bad (it doesn't), but there are so many white cars out there in general, and about half the recent Golfs out there in my locality are white and the GTI/GTD don't stand out massively against the SE/GT to the casual glance, so it looks just another Golf in a sea of white.