the user's speed will only be as quick as the speed of the websites/games/service that is connected
Of course, which is when we went from an old 512kbit/sec ADSL to 8mbit/sec ADSL here, very little difference was seen in general usage, for most sites, many of which have latencies of seconds or even (especially with some online banking sites) tens of seconds.
The place you see a difference, potentially, is on straight file downloads from a very fast server. A friend is on 80mbits/sec (Brighton) and he is actually getting that, on file downloads.