Well, my advice to you is to get one, it saves the hassle of running out of USB Ports. Most USB Hubs require the usage of one existing Port on you PC or Mac, but this is compensated by four or more on the Hub itself. If you are going to use just Digital Cameras, Printers and USB Memory Sticks that's fine. However, if you are using USB Disk Drives, I would recommend buying a powered USB Hub and a well known brand, like Belkin. I did buy a lesser known brand sometime ago and it suddenly stopped working. Also, USB Disk Drives that need to use two USB Ports do use, ironically, a little bit more power. So, a standard USB Hub probably won't be up to the job. I usually use a USB Port from the rear of my PC, leaving the front two Ports at the front space for USB Memory Sticks or for powering an external USB Disk Drive. While I leave you with these thoughts, check out the USB Hub video below :
I was bought this USB Hub for my Secret Santa present in December 2010, little did I know that it changed colour. So it was a pleasant surprise when it did.