That question depends on what you use your home network for. If you are a gamer and use your home network to just play video games you do not need a Gigabit Switch. A network is only as fast as its slowest link. If you are using a cable modem with 10 Mb of bandwidth there is little or no reason to have a 1000 Mb (1Gb) pipe from your device to the modem. A gigabit switch will not make your connection to the online server any faster. Though bandwidth allows a user to move more information from point A to point B, it does not necessarily make your response time faster. Also, the fastest you can connect through a 10 Mb cable modem is 10 Mb, that is where the pipe gets clogged. Your internet bandwidth from your internet provider determines the speed, not your home network.
On the other hand, if you have many devices within your house hooked up to your network, and you wish to transfer large amounts of information across this network. A Gigabit switch will increase your capacity on your network and allow for this transfer to happen faster within your local network.
Something to note though is that all the devices you are connecting to the gigabit switch must also have Gigabit network interfaces to operate at this speed. Most network devices do not have Gigabit capabilities, but rather the standard 100Mb network connection. Fortunately, many new devices do have this capability.
To recap, a gigabit switch will not make your cable modem go faster. But, if you want more capacity on your home network for transferring videos and files then you should invest in a gigabit switch or router and gigabit network cards for your devices.