Hey there! Some of my favorites include Glengoyne 10 year, Balvenie 21 year Portwood (expensive), Macallan Cask Strength, Glenmorangie (all of them!), Cragganmore 12 year, Glenfiddich Solera, Glenrothes (1987, 1991) - their Special Reserve is reasonably priced....
If you think he might like peat, smoke - consider any of these brands: Ardbeg, Laphroaig and Lagavulin. I really enjoy Laphroaig Quarter Cask.
Good luck - let us know what you decide!