Hi, i am Scottish and have lived in Scotland all my life. The nearest distillery to me is Glengoyne, 10 minutes along the road. Well worth a try if you have not already. I am not an expert on whisky but collectable bottles are for example and as others have said, whiskys from a distillery that has since closed down, making them extremely rare. Another possible investment is a single cask where there are no other whiskys blended in with it. Also look out for special editions that have a limited number of bottles with each bottle having a number and certificate of authenticity. It also depends on how much you are willing to spend. I had a look at a 40 year old Glengoyne for a friends birthday and it was £2,500! Got him a 21 year old instead!