Regarding bandwidth, I don't notice much difference in my internet experience now, currently on 10Mbps Cable, over what I used to get (2Mbps cable)*.
I find that the bottleneck shifts elsewhere, usually to the server / internet connection of the site I'm downloading from. Also, as internet connections have increased, so also has the amount of data associated with web browsing - e.g. ads on PPRuNe, BBC iPlayer (I wish it didn't exist).
*The cable company has just upgraded the connection over the years, 2 > 4 > 10. I may even have started with 512K, it's been a while!
SD