Pool Cues
In order to have a complete billiards room, you should have a wide variety of pool cues. Many players, both professional and amateur, have their own preference in weight and length. If you don't have a good variety of pool cues, you may disappoint your fellow players.
Most importantly is the requirement of different lengths of pool cues. People come in may shapes and sizes, and if you're entertaining a large group, you'll want to make sure everyone is accommodated. No one likes being left out because they can't play properly.
Even children deserve the right to play, and it's nearly impossible for them to play well with an adult size of pool cues. So make sure you have a couple of shorter sized ones to play with, this is especially important for people who entertain large families, the children will want to play. Remember, they come in a variety of shapes and sizes.