Whiskey, or Whisky, is intended to be served neat (without ice) at a temperature of 59-65 degrees. This temperature is the average room temperature of traditional Scottish parlors before there were central heating systems. In Scotland, where whiskey originated, fine whiskey is distilled to taste best at this temperature range.
The best way to bring the temperature of your whiskey to this temperature is by using whiskey stones.
Cooling whiskey to the ideal temperature of 59-65 degrees with ice will do two things that can ruin a fine whiskey. First it will cool the whiskey well below the ideal temperature. One standard size ice cube in 2 ounces of whiskey will cool that whiskey to 45 degrees in under five minutes. Second it will water down the flavors of the whiskey as the ice cubes melt. For those people who like to add a little water to their whiskey, using ice is not a good way to do this. You can not control the volume of water and your can not always control the type of water that the ice cube is made of. You are much better off adding water yourself than counting on a melting ice cube to do it for you.
If you do not cool your whiskey, as the whiskey sits in your glass it is constantly subject to warming from your hand as you hold the glass. This will bring out the alcohol in the whiskey and make for a harsh sipping experience.
Whiskey stones are soapstone rocks that when used properly, cool your whiskey to the perfect temperature. They are easy to use. Just take 2-3 stones out of the freezer and put them in 2-3 ounces of whiskey, let it sit for five minutes and you are ready to enjoy perfectly cooled whiskey.
The whisky stones impart no flavor on the whiskey and do not introduce any water into the whiskey. They will hold their temperature well for over 30 minutes. They are completely reusable.