Come on this old ground been done to death, yes there is the unlimited option but I`m pretty sure if you max your line out 24/7 you will get your collar felt. My last ISP Bethere prided them selves on the truely unlimited tag but IRC a few individuals getting the heave for going crazy.
However I think BT have made it pretty difficult to download 24/7 due to their use of traffic management. You know there is more to having a nice fast line with plenty bandwidth other than maxing it out 24/7!
Remember: Amateurs...built the ark.
Professionals...built the Titanic
All spelling and grammatical errors are left in on purpose