I would consider myself a bit of all 3; drinker, collector and investor.
Having the great fortune of living in Japan for 4 years I was able to easily get my hands on some Japan only bottlings (e.g. Springbank Saxplayer), cheap Macallan Gran Reservas (1980s sold for $105 at a popular convenience store), some cheap Ardbegs.... Many collectable Springbank, Ardbeg and Laphroaig usually sell for less than current "market" rates outside of Japan, while Lagavulin, Bowmore and Macallan (with exception of the Gran Reservas) usually go for higher rates.
So what I did was start off with a small collection of drinking and collecting whiskies and gradually accummulated then either sold some to finance other purchases or traded up for other other whiskies I was interested in drinking/collecting. The result was that I now have approximately 200 bottles in my collection that are typically deemed as collectables and the vast majority are also considered great drinking whiskies. Through this buy/sell/trade approach the monetary benefit is that the estimated value of my collection is almost 50% of what I have actually spent in cash.
Being a realist I know I will probably not be able to drink all of these (although I will give it a good shot) and when the time comes to sell off some of these I should be able to fully recoup the money I have invested.
So the net effect to me is:
1. I will either recoup my full investment or maybe make some money off of the bottles
2. I can finance the purchase of and then drink bottles that I could not otherwise afford to buy/drink (I have earmarked for future drinking some vintage Macallans, Springbank Local Barleys, a bottle each of the Manager's Drams, Ardbeg Committee bottlings (and other Ardbegs), Laphroaig Feis Ile bottlings and a Black Bowmore). This would not have been possible if I was doing a straight buy and drink approach as I simply couldn't afford it.
3. I am able to entertain myself with a great hobby that allows me to make many new friends
Not a bad deal in the end