The most venerable of spirits :-) But why oh why is it called 'scotch'????
What's the difference between whisky and whiskey? Apparently the original spelling was 'whiskey' but unusually for the (British) English language (as opposed to US English), the accepted spelling came to be that without the 'e'. Now the distinction is that 'whisky' refers to Scotland's version while 'whiskey' refers to Irish and American whiskies, thought it's definitely not a hard-and-fast distinction. (See the Wikipedia entry on whisky.)
Some links which I've (still!) yet to sort through: