When it comes down to the details of your wedding one important decision that needs to be made is whether or not to make a seating chart for your guests. Typically, when you are having a sit-down plated dinner, most caterers ask for a seating chart including place cards for the guests to help determine dinner assignments.
For a buffet-style dinner reception, it is up the bride and groom to decide on a seating chart. One big advantage electing for a seating chart is to ensure that families and couples are guaranteed to sit by each other. Either you can assign a table with a escort card table or an actual seat (placecard already at the seat and signage directing guests to their table).
Escort Cards: Displayed near the entrance of the reception in alphabetical order, they usually include the guest's name and table number. Used in the most formal seating plans, escort cards usually contain the guest's name on the outer envelope, and their table number on the card inside. Place cards await guests at each table, designating their seats.
Place Cards: We typically see Place cards used at more formal events. These are cards that do exactly what they say... they tell your guests their "place" at their table. It will have their name on it and if you've had them select a specific entree will usually have some way to designate their entree choice (color, ribbon, etc).
The Seating Chart: Usually displayed alphabetically in a pretty frame or another creative fashion near the entrance of the reception, seating charts are lists of guests' names with their designated tables.
Here are some examples I've found for inspiration: