It has to be any decent Speyside Single Malt. Fortunately my wife is a bonnie lassie from Aberdeen (near Speyside) and my brother in law used to work in some of the local distilleries.
Some to look for
Aberlour
Glenfarcus
Auchroisk
Glenfiddich
Glenlivet
Millburn
Tamdhu
e told me about a great site to get great whiskey at exceptional value (we brought a 28 Year old Glenlivet for 95 pounds for my Grand fathers 100 th Birthday!! (yes 28 yr CASK MATURED for 95 pounds) which would easily cost 2-3 times as much in a shop. The thing is you couldn't buy this from a shop anyway, it would probably be inferior bottle matured). It was the nicest whiskey I have ever tasted, just incredible.
They buy casks of whiskey directly from the nearby distilleries leave them mature for say 18-28 years then bottle it themselves. They are based in the little village of Huntly which is in Speyside. We went to visit their factory a couple of years when we went to visit my wife's family- So THE genuine article and the place to buy whiskey at incredibly low prices (do a comparison yourselves)
I promise we have no business or personal affiliation but take it from me if you want exceptional whiskey at exceptional value go to Masters Of Malt. They know their whiskey and supply many retailers and online websites so go to the source and cut out the middle men. Ask them what is good or not and they will give you some great advice.
http://www.masterofmalt.com