Depressingly boring business casual (yick! biz-caz!) or lacquered 50s housewife in fashion-before-function heels, red lipstick and red nail polish. Always red lipstick, always red nail polish.
Side note: If I were able to fill my entire closet with dresses and cardigans, suits and accessories from the 40s and 50s, I would be the happiest little clam you ever did see.

Well, it would have to start out by serving an excellent Margarita. That is one of the key ingredients for a good bar. I am not talking about frozen Margaritas either; I want tequila, triple sec and fresh lime juice (no sours, ick!), shaken with ice and strained into a salt-rimmed goblet. This Margarita should also be made available with a shot of raspberry or mango syrup (sugar on the rim and a thick wedge of lime), if one feels like straying far from the norm.
Said bar should be fully stocked with liquors, liquers, wines, beer (the good kind), mixers and garnishes of all varieties. These beverages and ingredients will be mixed, sold and served by a highly knowledgeable, affable and sharply dressed staff. They will be reasonably priced and never too strong nor too weak. Red Bull and vodka will never, ever be served (apologies to my darling Paul, who adores this vile concoction) and PBR will not find a place there: nary a can, bottle or tap to be seen!

Artful presentation is an absolute must. Beer will be served in its appropriate glassware. Cocktails will be served in a charming array of mismatched, authentic, antique glassware appropriate to the elixir contained within. Garnishes will be lovingly crafted for each beverage. One will gasp and shiver with pleasure when a beverage is first presented, barely able to ruin such a beautiful sight with that first sip (and, oh, that sip will be blissful).

Now, to the menu: I could elaborate on food forever, so I am going to restrain myself quite a bit. The tables and bar will always have baskets of fresh, warm tortilla chips and cool salsa fresca. The menu itself will contain a wide variety of delectable, savory appetizers for both the animal loving and animal eating. No full meals will be offered! Also featured on the menu will be a small but lovingly selected offering of rich desserts and crepes. The food will be divine, as divine as the drinks, and will be presented on mismatched antique dishware.

Décor and ambiance! This is both a difficult and easy one to envision. This bar will be of the medium-sized variety: Not so terribly big that you get lost going to neither the powder room, nor so small that you have to squeeze your way in on even a weeknight. The walls will be painted some sort of a deep red shade; warm and dark, but not stifling. The bar should, of course, be dimly lit with lighting sconces of the 40s or 50s variety. Candles will flicker atop each table and, in addition, at the bar. Oh, did I mention tables? How silly of me, as that makes one think of tables and chairs. I meant booths, booths, small booths and big, glorious booths. Booths will be everywhere, with plush, comfortable seats and gleaming formica-and-chrome tabletops. Patrons will relax and luxuriate in these booths, able to enjoy conversation, their drinks and their snacks. Speaking of conversations, the music will never, ever, ever be too loud. You must be able to chat without yelling. However, a juke box will be available and, in my fantasy world, it will only cost a quarter to play a song. As my own musical tastes are rather mercurial, I can't properly describe what tunes the jukebox would hold. Let's just say that they'd change on a fairly regular basis, with a few old stand-bys for posterity's sake. People do like their comfort tunes.