When I got my VDSL line installed at home about 3 years ago with a 25 Mbit/s downlink and a 5 Mbit/s uplink I wasn't actually quite sure for what I would use such high speeds. At the time, most servers could not deliver data at such high speeds anyway. This has changed in the meantime, however.
While for web surfing such speeds are still far beyond what is necessary today, there are a number of services that make good use of the available bandwidth by now. My online video recorder, save.tv, has been capable to send me the recorded videos at my full line speed for a while now. A full movie recorded from television at my home in just a few minutes. Also, downloading Linux distributions to experiment with are now usually also downloaded at full line speed.
The 5 Mbit/s in the uplink are also taken into good use in the meantime, for example for my private VPN at home to tunnel my mobile Internet connectivity from my PC for privacy and security reasons through my network at home. As all data goes through the uplink, the highest speed I can get over the VPN is not 25 Mbit/s but 5 Mbit/s. Still enough for most purposes but if it was any slower the solution would be far less usable for many purposes. Also, I sometimes have to share large files with other people and don't like cloud based solutions such as Dropbox for the purpose. Instead I store the files on my NAS at home and let the recipient access the files via https. Works perfectly and the 5 Mbit/s are put to good use for this service as well.
OS and program updates are now usually also delivered via content delivery networks and a 50 MB update is downloaded in a matter of seconds instead of saturating the line for many minutes. And finally, Skype video telephony also makes good use of a fast uplink, perhaps not the full 5 Mbit/s but at least 1-2 Mbit/s for very good video quality. With a 5 Mbit/s uplink, other services using the network simultaneously do not get in the way of the transmission.
And I've only talked about single use so far. When you have kids at home, each with a computer and other gadgets accessing the Internet, even such a link could become congested sometimes. Time to think about the next step and perhaps put some traffic shaping in place :-)