I am looking for a special gift for what I might term an"advanced beginner to intermediate" single malt drinker.

He has stated in the past that he likes the very smooth, vanilla/toffee richness of a Glenrothes, so I am assuming that's his preferred style.

I'm looking to spend around $250 USD but I'm not beyond spend $300-$400 USD if it is truly a "wow" level single malt that he'd be completely over-the-moon about.

Suggestions??