One version of the classic Manhattan cocktail:
2.5 oz. rye whiskey
1.0 oz. sweet vermouth
dashes orange bitters
garnish: cherry OR lemon/orange zest
Mix with ice, strain into chilled cocktail (Martini) glass.
Good bourbon may be substituted for rye.
I started using the Manhattan as my default cocktail (When unsure what to order, I order this, assuming I want something fairly potent.) as it can take a fair amount of abuse in varying ingredients and quality thereof. Typical rail whiskey and even poorly treated vermouth still makes a tolerable Manhattan. One which is honest and up front tells you it will kick your ass if you aren’t careful. But use a top shelf rye, a well-cared for high-quality vermouth and it becomes downright dangerous: A delicious drink that greets you with “Hi, Friend…” but it will still kick your ass if you aren’t careful.
Should you happen to ever see me sitting at some bar (or restaurant that serves drinks) please do NOT buy me a drink without asking about it. I once had a well-meaning fellow buy me what was my fourth (I think.. it might have been “only” my third) Manhattan. And that was Rather Much, even though I had been switching to water between cocktails to help stay hydrated and even things out some. Fortunately this was at a convention after I was well and truly done for the day and evening and had NO plans beyond fairly mindless wandering about and sleep.
 Do NOT use Jack Daniels for this, though! I had the worst, and one of the best, Manhattans at the SAME place (in Manhattan, no less) as a new bartender made me one with Jack Daniels. A more experienced fellow, who I’d complained to, made the next – with Maker’s Mark. Talk about going to opposite ends of the spectrum. This wasn’t IR to UV, but longwave to X-ray.
 Unless a place serves Martinis frequently, do not order one. The Martini is very sensitive to ingredient quality and vermouth from a neglected half-empty, dusty bottle will result in nothing worth drinking. And, yes, a Martini does need vermouth. One sans vermouth is merely gin. If you want gin, just order/drink gin and be honest about it.