Here we get about 5MB down on ADSL, you can reliably view youtube without buffering at 1080p and it will be OK at 1440p at quieter times
The upload is a tedious 373kb though, it might not be an issue but sooner or later you'll probably be pleased to get a much higher up speed than that. 
Closer to the exchange fibre is now widely available with speeds up to 100Mb, it's not clear to me anyone really needs much more than 20mb unless there are several users.
You soon  get to the point where other factors are a new bottleneck - the router speed for a start.