A friend of mine finished building one and used a fire retardent material / finish (so he could light drinks on the bar). Make sure the top is sealed, bare wood will soak up moisture (marine varnish is an option).
Also include: - paper towel dispenser - location for clean glasses - location for dirty glasses - Room or a display for liquor bottles (if it's not a beer only bar). - a large bin for ice - a source for water (clean the drink mixers, etc.)