As best as I can make out at the moment (made redundant from telecoms 3 years ago!), the next logical and achievable step for the UK is 'ADSL 2'. However, Ofcom hasn't ratified this yet so we're presently stuck with the ADSL flavour which was original developed about 20 years ago. SDSL, which is currently available, would make life sweeter but pricing and capacity is the issue. VDSL (very high bit-rate) is also looming with a theoretical throughput of 52Mbps (get back in your wheelchair, Timmy!)
Currently, it is possible for SPs to beat the limitations via Local Loop Unbundling (LLU), whereby the SP is allowed to install their own DSL delivery equipment in the BT exchanges and so deliver their own product to the customer over the last leg of the link. Bulldog have been very aggressive in this respect, but the real key for the rest of the SPs is for BT to stop being generally obstructive and lower their LLU charges. When I was working with National SPs in Italy, Spain and Portugal upto five years ago, LLU was already a done deal in line with ITU directives. I've got absolutely no time for BT or Ofcom. European telcos must look at BT and wonder how on earth they can get away with it.
Don't hold your breath whilst waiting for Ofcom to pull their finger out, either. As people start losing patience with them and their toothless approach, at least one of their major decisions viv-a-vis BT has come under Select Committee scrutiny. Watch this space.
Although the UK isn't the worst place in Europe for broadband, some of our neighbours fare much better for either pricing or 'girth of pipe' (or both). It is possible to get 100Mbps - synchronous! - in Sweden for less than £44pm, uncapped 20Mbps ADSL 2 in France for £20pm and .5Mbps in Germany for less than a fiver a month.
Much of the Japanese network is shifting to fibre optic, and that brings some mouth (or eye) watering results with it: how does Usen Network's 100Mbps for £15pm grab you? You can get 50Mbps from Yahoo Japan for £21. Here's my take on it, though. About for years ago, we all got taken in by the Dotcom fiasco. Obscene amounts of money were squandered and there were serious consequences for many telcos who gambled at the tables. In the Far East, where the financial bubble had burst sometime previous to all that stupidity, the money simply wasn't there to speculate with. So they didn't get their feet wet. Instead they started investing shrewdly and heavily in network infrastructures.
They'll be teleporting to work while we're still waiting on the platform for a train that will never arrive. Probably.
ps - many facts and figures here were lifted from a rather nice little weekly computing mag that I won't mention here for fear of being excomunicated.