According to GeekSquad.com:
Generally, this is the lowest level of service available in most areas. Email and most web site will load fine and most music streaming services will work without interruption. Internet phone services (VOIP) should have no trouble. But Standard Definition (SD) videos will buffer on occasion.
According to the Federal Communications Commission, this is the minimum speed "generally required for using today's video rich broadband applications and services." Users at this speed should not have any trouble with streaming audio or video. Service at this speed will allow some file sharing and should work fine for streaming Internet TV (IP TV).
For online gamers and heavy video-on-demand, this is the preferred speed. This speed delivers uninterrupted online gaming and smooth on-demand video as long as only one device is using a high bandwidth service.
Geek Squad also goes on to mention that average users getting above 10Mbps typically do not notice the difference in speed.