At some point the UK is going to have to put out Fibre networks in places like South Korea and japan you can easily get 100Mbps+ as standard (however the logistics in those countries are vastly different) , the question is what is the best option, is there a best option?
Currently we all have broadband which is between 1Mbps and 20Mbps, realistically you will never get 20 thought however I believe the advertising standards agency is changing the regulation so the companies have to give a realistic average speed of what you get rather than what you theoretically (but actually will never) get.
Option 1 is to put it to a routing box which will supply a whole neighbour hood, this is of course the cheapest, but also never gives you the actually speed of fibre due to what is know as the last mile problem which is where the last mile or less of the cable is slow and therefore limits the bandwidth you can receive.
The second option is to have a share cable to all the houses costing a lot more but giving you a decent speed internet meaning you can do whatever you want with it such as download HD movies and watch porn all day, which is clearly what the internet was designed for, in more prosperous usages it will also increase the rate of video conferencing and the ability for people to work from home logging into there companies networks. Other advantages also include the uptake of cloud computing meaning you won't have to store all your data on your own computer which might become corrupted and will be able to upload it to a massive server regularly to back it up.
The third option is to put a cable to everyone's house which will give you all the features just a lot faster, 2-4x faster in fact.
My personal opinion is all of them but for different places, fibre to street level should go out to the rural areas as to keep them in the loop but not to make the cost per head of the service ridiculously high. Everyone else should get a shared connection to their house giving them 250-500Mbps, which the ability in the future for the company to attach a fibre to each house to upgrade it and with that plan in mind, but it would be better to get it out to the most people possible first.
50Mbps will be good enough for most, it will just take 10 minutes instead of 1 to download the video you want to watch and things like HD Internet TV and cloud computing won't be as readily up taken in more rural areas, but if you get fibre out to the cities and the suburbs the there will still be a vast uptake.