The key to a successful event - any event - is 1) creating an environment where your guests are comfortable and 2) exceeding their expectations in small ways. Both of these can be done on a tight budget and neither requires you to go overboard on ~~rules~~. Having an ettiquite-nazi in charge puts everyone on edge because they'll spend the entire time wondering if they're measuring up and doing things right.
The key to a good event is enough booze ;-)