cash bar = tacky, as many have said. if you charge me for drinks at your wedding, that nice big check i was going to write to you for a wedding present is going to get reduced accordingly, and i'm going to think you are a cheap bastard, you can count on that.
we specifically invited less people (sorry aunt mabel who i've met 3 times in my whole life) to our wedding so that we could afford to have things like really nice appetizers (like a raw bar with crab, jumbo shrimp, clams and oysters, and yes, lobster), and yes, an open bar with top shelf liquor. we even had a 2 hour cocktail hour instead of 1 just because that is the part we thought people enjoy the most at a wedding. we had a steel drum rasta band playing during that part too, people loved it.
when it was all over, most of our guests told us it was the best wedding they had ever been to. and people HATE going to weddings, so that meant alot to us. i always tell my wife i wish i could have been a guest at our wedding.