Minecraft wiki entry for Train_station, associated text: Maps in item frames. This can show people where they are going.
Shops. A small trading station where you can buy and sell things from a server user. You could also add more shops that use villagers for trading purposes.
A mini restaurant. The meals could be cooked meat and the drinks could be potions.
A goods station. You could use this to send storage carts to your friends.
Some ender chests for secure transport of goods, even though this cannot be used to send items to others.
A clock in an item frame.
For some added fun make mobs occasionally fall to their deaths, giving free items.