I get the feeling Broadband is going the same way as digital cameras. The digi camera companies know that the vast majority of consumers now only take into account how many megapixels a camera has and immediatly equate more = better (i.e. 8mp is much better than 6mp). Of course all other things being equal that's true, except all other things aren't equal.
Broadband has gon the same way. 20mb must be twice as good as 10m. If the cable companies backbones and websites etc had unlimited bandwidth to cope, and low latency connections that might be true. But they don't.
To be honest, I'd much rather have a 2mb low latency, low contention reliable connection than 20mb high latency connection that suffers from disconnects.
I have to ask, what on earth does anyone use 20mb for other than the odd download of a demo?