I moved up from a Baby Saz to Booker's tonight, and the straight face is a little harder to maintain. I've gotten used to the higher proofs (100 and above) so it's not as painful as it used to be.
Here's a tip; when we eat or drink, our natural tendency is to press the tongue into the roof of the mouth. It helps distribute food and drink to the entire surface of the tongue, making all our tastebuds feel like productive members of society. If you can resist doing this when drinking kick-ass proofs at first you will have an easier time handling them. Soon enough you'll be able to coat your tastebuds in Hell Juice without flinching. Then you can begin working on your next challenge: Eating the Bottle. Your friends will be amazed.
I have always consumed the vast majority of my whiskey neat from the very beginning. Only lately have I begun to understand the pleasure to be had in certain whiskey cocktails. I find bourbon + ginger to be a better alternative to neat drinking in social situations, for instance. I enjoy neat drinking more when I'm by myself.
I want to learn more about whiskey cocktails. I just haven't made the time yet
Proof-wise, I usually love any whiskey up to 120 proof. I can and have drank the Staggs and barrel proof BTAC's neat, but the flavor gets too concentrated and hot for me. And much less gentle on my head the next morning :)
I find that the more you drink straight, the better you get at drinking ultra-high proofs (and the better they start to taste). But if you take occasional breaks from all whiskey drinking like I often do, you will lose that tolerance pretty fast.
If you want to get some background on whiskey cocktails, a good start would be the videos on the Old Fashioned, the Manhattan, and the Sazerac by Robert Hess. I'm a fan of OF's and Mahattans, and I pretty much use his recipes as a starting point (I personalize my Manhattans by adding in a few drops of Fee's Orange Bitters, for example.)
Neat is hard to beat, but I sure enjoy a well-made whiskey cocktail, especially a good Manhattan.