+1 on splashing in a little water to bring out its bouquet...just make sure its a good quality water...something on the soft side (low mineral).
I've been adding a single cube of RO ice to about a finger of scotch (or bourbon) and I'm liking it.
Have you tried it neat with just a splash of water? Go pick your favorite barley wine and chill it until it's ice cold, then drink it up quickly. What's the point, right? All the complexity is dead. Same deal with scotch.
I love how even the smokiest scotch will leave behind more and more fruity/sweet/butterscotch aromas as you drink it. Sometimes I'll leave my glass unrinsed overnight just so I can smell it in the morning.
+1 Just a very small splash of water will open up the whisky, but too much will drown it, water down the mouthfeel & flavor. The only time I use more than a few drops is in a cask strength whisky. but that said.... it's all personal taste. but do try it with just a splash... you can add more if you like, but you can't take it back out. well, I guess you could just add more whisky

and +1 on leaving the glass till the next morning. I'm used to hand washing my beer glasses, and I usually do it right away. I bought some nice glaincairn whisky glasses a number of years back, and so I hand wash those too. Everything else goes in the dishwasher. Well, one night I just left the whisky glass on the kitchen counter after a late-night dram of Springbank. When I came into the kitchen the next morning I could smell the malty richness across the room. What a pleasant surprise.
That's a testament to how a whisky opens up and changes. Drink it slow, linger over it and appreciate it. The Water of Life is truly a gift and a blessing.