When installing a surround sound system you will always want the best sound you can possibly get and there are a lot of factors that can make or break the sound quality. The most obvious factor is the quality of speakers. If you have very low end speaker you will get low end sound. They may even end up breaking after a few years. The next factor is the receiver or DVD player that you are using to play the music, television or movie. The most overlooked item when buying a surround sound system are the wires or cables used. These play a huge factor, but, are also the most likely item to be overlooked. Even the length of the cable can play a role in the quality of sound.
Obviously, you will want good speakers because they will produce better sound. But like most people you are probably on a budget and can't speaker $1,000 or more just on speakers. The best thing to do is find out what you budget is and buy the best speakers for your money and buy the speakers that will be suitable for your needs.
The amount of watts and quality of receiver plays a role in the quality of sound you will get with your surround sound system. It may not play as a big of a role as the speakers or audio cables but it still can make a difference. It will also control out loud your system can output the audio.
The most overlooked item is the audio cables. The cleanest sound comes from audio optical cables such as TOSlink cables and SPDIF cables. The higher the quality of cable you use the cleaner the output audio. The material, distance, and type of cable all play a role in the overall outputted audio quality. TOSlink cables can carry a very good stream of audio but you need to be careful of bends and turns because that can cause some of the audio to be lost. Keep in mind the longer the cable the more likely you will experience some loss in your sound. A weak and thin audio cable will produce a weak and thin stream. A lot of the time your system will come with cables but you may want to look into upgrading to your own to achieve the maximum audio possible.