Two of my most useful are the snifter and the shot glass. The snifter works well for Port, Scotch, liqueurs, as well as "big beers". The shot glass is never used in my house for tequila or vodka, but rather for sauces, tiny tastes of soup, and occasional measuring for a cocktail.
From left to right, starting with the back row (favorites with an asterisk):
- martini, Cabernet Sauvignon crystal*, Pinot Noir crystal*, Gruet-inscribed Ridel sparkling crystal*, standard sparkling wine glass,
- Italian crystal red*, lager glass, generic wine glass, small generic wine glass,
- pint glass, Remy Martin highball* (great for small cocktails), crystal snifter*,
- 3 oz. shot glass, tall "shooter" shot glass,
- standard shot glass