Oh blimey - what a question!
The problem is that malt whiskeys vary enormously, and can be a very personal thing.
Laphroaig and Talisker are both extraodinary, but not to everyone's taste (Laphroaig is rather "seaweedy", while Talisker is usually described as "volcanic").
Glenlivet, Glenmorangie and Glenfiddich are all perfectly good malts, but I've known some people turn their noses up at them because they're as commonly available as many blends (more fool them, I say, but never mind...)
Apart from those, a couple I like are Aberlour and Dalwhinnie.
If you're unsure of the gentleman's personal taste, I'd recommend going for an older malt...