I live just outside a small town, and get a stable 1.5Mbps ADSL maximum due to my distance from the exchange. I currently pay for 'up to 12Mbps' because that's the cheapest package on the ISP I want to be with (bethere.co.uk) - fibre is not available here, and neither Virgin or BT have any plans to bring it here due to the lack of commercial viability.
The question is: Who is ultimately responsible for the quality/speed of the infrastucture? To me, this is an issue with my BT phone line, not my ISP.