Unless you live in an LLU area then the likelihood of getting 8mbs with a BT line and any isp is going to be a reality only for a few close to exchanges, no matter what all the hype about BT opening up sais. The Register also reported that BT is opening up exchanges/lines first in LLU areas in a snide way of undermining companies that are threatening them.
NTL are supposedly enforcing caps later in the year and as an NTL customer I'm gonna sit back and see what happens in both camps. So it'll be 3mb rape until the cap comes in for real and I'll move to an unlimited adsl muller, probably ukonline 2mb deal. I'd imagine the reality will be the speed hungry minority being disappointed people later in the summer; as BT opens up more exchanges etc. which, results in limited gains for that cohort. Then again, the majority would be more than happy with 2mb and some capping which isn't helping getting speeds upped. NTL for example were reported as being more concerned with keeping its mass of lower tier users, as opposed to the speed hungry crowd and hence came the idea to force a cap and ease traffic/strain to their systems. The only hope here is that NTL rethink the forced cap due to losing not only bb from it's customers who leave but tv and phone line revenue too.