Do you need to replace your old coffee table? If so you need to consider a few things before you go out and make a purchase.
You need to consider the current design in the room you are planning on putting the table in.
How are the furnishings in the room situated? Are they circular? If they are circular you are going to want an oval or round coffee table.
If the décor and the furnishings in your room are set up in a more square layout then you definitely want to find a square coffee table.
This is a very important decision to make as the coffee table really pulls the room together.
The table is the core of the room (kinda like the center of the spokes on a bicycle wheel).
All of the flow in the room is directed from the center so the table needs to match the flow.
If you have a lot of pictures or paintings on the wall then a square coffee table will be best (unless the pictures and paintings are in oval or round picture frames).
Do you have square end tables and a square entertainment center with a square television inside (I've yet to see a round televison)? If so then a table with a square design is definitely going to match it.
You can find square tables in any type of style with any type of design.
Modern and traditional tables can be found in square designs.
It really is up to you to make the decision based on your current décor and the room's current set up.