generally I follow the following rules: 1) If I know the restaurant permits corkage, I will just bring a bottle. Also, I will try to research the list in advance so that I do not bring something from a producer that is on the list. For instance, I thinks its bad form to bring a 1985 bordeaux when the restuarant has the 1989 of the same producer. Now if it was a 1961 or 1970, I would find it more acceptable. 2) I'll always offer a glass to at least the somelier and others depending how many are in my party. 3) The hardest decision I always have is deciding what is acceptable to bring. Generally, I try to bring soemthing that I think would cost in excess of $150-200 if it was on the restaurant list. Some of the recent things I have brought to a restaurant are a 1981 Margaux; 1986 Talbott; 1990 Pichon Baron and 1984 Insignia. 4) I normally take the inconspicuous approach and bring the bottle in a small shopping bag. 5) I generally add whatever the corkage fee is to the tip. 6) In NYC, I've generally encountered a $25 fee. However, I would pay more (upto $75) in order to bring a special bottle to a restaurant and avoid being raped on a 3-4 times mark-up. I find it hard to walk into places such as daniel and you look at the list and everything is 3+ times the price that one can find it for with minimal effort. For me, it takes away from the enjoyment of the experience.