Sure, you can toast the marshmallows over a crackling indoor fireplace when it's cold outside; but for me, you can't beat a summer night, a whittled stick to put the 'mallows on, and a comfy log to sit on while you cook them. There's something about the earthy scent of the outdoors, a light breeze, the colors of the sunset...
Before I start waxing poetic, let me make a few logistical points. There will always be a place in my heart for the standard grocery-store s'mores components; Jet-Puffed, Hershey's, and HoneyMaid should be part of every kid's s'mores experience. But let's think about making them grown-up for a moment. How about homemade marshmallows and graham crackers, and a really high-quality chocolate?
As far as chocolate goes, there's no need to get all spendy on the super-handmade stuff (though of course you're more than welcome to). Scharffen Berger is always my go-to for a nice snacking chocolate; and their milk chocolate has a nice deep flavor that works perfectly in s'mores. But your favorite eating chocolate should be just fine.
I also can't really do better than Smitten Kitchen's marshmallow recipe, either. I would suggest cooking the syrup a few degrees higher (243-245°F, perhaps), though, for these purposes; they normally set up nice and soft and fluffy, but you want a little more structure when you're toasting them.
In my opinion, it's the homemade grahams that really make this dessert. The crunch and texture really provide a solid base for everything else. If you somehow end up with leftovers, you can snack on them plain or crumble them over ice cream.
So make these homemade graham crackers and have a bougie S'more or two. I promise I won't tell your inner child.