My son's six, and he still usually has milk/warm milk/hot chocolate, before bed.
We laid off for a while he was potty training (for about a week, until he got getting up to pee down). Aside from that...it's part of our ritual. He drinks his warm milk and we talk and he goes to sleep.
Remember, you never HAVE to do anything (transition-wise). It's all about what works best with your family. We never tried to discourage it, because we don't feel there's anything wrong with it...but to each their own. We also don't have any dental problems...if we did we might have traded the milk for water.
:)
Z