I agree you should have some sort of refreshments at the party. I am sure you don't want your guests getting plastered the night before the wedding, but I would have a selection of sodas, bottled water, and beer for the guests. I like the idea of using a galvanized tin and decorating it. If it is an outdoor affair it will be perfect. I don't know how many people you are planning on having, but I know when we have parties at my mother's house we always use a cattle water trough and fill it with ice and water. (don't worry, that's all we use it for, not for cattle too). You also said you would hate to use plastic glasses, but there are glasses these days that are plastic but look like real glass and are very durable. Hope this helps!