When it comes to enjoying the drink, the goal is to EXPERIENCE the drink. This is done by enjoying its color, its aroma, and its taste. To drink Scotch Whisky in a red, plastic Dixie cup is to still drink whisky, but it does not lend itself to enjoying the whisky, as you cannot either see the whisky nor get the taste of a cheap plastic cup out of your mouth.
My grandparents had these aluminum cups from the 50's or 60's. Anything I drank out of them tasted the same (metallic). This is an example of what NOT to drink your whisky out of!
Selecting a whisky glass is SOMEWHAT of a personal decision, but there are reasons why the glass in the address bar is a Glencairn glass.
The Glencairn is perfectly shaped to best "nose" the whisky, and the bell at the bottom allows you to see the whisky's color. It is clear, and not etched, so you can watch it move about in the bowl. It is small, as drinking a nice dram should not be a rushed affair, but a time-consuming event. There is no room for multiple cubes of ice, or large amounts of water, or other cutting agent. This glass is intended to be used for the tasting of fine whisky, taken neat. For this reason, I refer to it mostly as a "tasting" glass, not a drinking glass. A tumbler is a drinking glass.
On the other hand, I also really like etched crystal brandy snifters.
I like drinking out of these glasses. It makes me happy. They still have big bowls for viewing the color, and the mouth of the glass is a bit focused (tapered?) They aren't meant to hold ice, water, or (forbid the thought) soda. All in all, I think snifters are the next best thing to a Glencairn tasting glass.
To experience the TASTE of the whisky, a glass or crystal glass is best. This should not be surprising. In addition, not all whiskies are created equal. I have whiskies that are cask strength (60% ABV), and others that are 40% (most are between 43% and 46%.) Some are non-chill filtered, others are. Most of my whiskies are taken neat. However, I have at least one whisky that I ALWAYS drop one piece of ice into, as I prefer it that way. I do this for many reasons, here are some: (1) the whisky is non-chill filtered, so when ice hits it the whisky puts off the most intriguing particles, which dance in the glass; (2) the whisky is cask strength, so it is better when cut; and (3) the colder ice creates the most amazing "caramel" flavors in the whisky, that water does not. So, putting a cube of ice into my glass when drinking Macallan Cask Strength is the only way to do it for me. I enjoy it most this way. However, most all other whiskies are at their best when taken neat, or with a very small amount of water. I have added too much water to a glass, and when that happens the enjoyment is lost. For this reason, I tend to drink my whiskies neat. I just drink smaller sips, and hold it in my mouth longer.
As for what to pair your whisky with, that is another personal decision. The idea is to enjoy the taste, not to overpower it. I like smoking cigars. I really like smoking cigars and drinking whisky. However, I save my best cigars to enjoy with water, and I save my best whiskies to be enjoyed without a stogie. I like to eat aged gouda, dark chocolate, or a salty snack with my whiskies. The flavors complement each other. But of course, if drinking a very fine whisky, I eat nothing, wanting to experience the whisky more fully.
The truth is, to get a true tasting of a whisky, you should taste it multiple times over different days. This assures you are detecting its true taste, and not something you ate earlier!