well you are looking at high spec asdl here, but if you want advice-hear this.
ASDL is changing. soon 8mb will become standard and when asdl 2+ comes out, there will be speeds faster this.
What we dont know is what isp's will update their speeds to the faster asdl.
BT and AOL probably will, but i dont know.
Cable WILL DEFINITLY get faster.
So i would sit back, for a few months, watch the asdl change and watch the isp fight.
Then when it has all calmed down, choose the best isp.
Personally i would go for telewest as they are cheap and will change.
If you want a solution now, that might not get updated to faster speeds in the future, go to
http://ukonline.com
They provide 8mb bb for £29.99. (and other slower packages, all uncapped) however they might never get any faster.
So, either go with cable, wait and see what hapens with asdl, or if you are impatient, lol, get the fastest u can now!
Hope this helps
Andymt