If your in a city centre or surrounding area you can't beat Be Unlimited, 24Mbit/sec for £24.

https://www.bethere.co.uk/homebroadband.do

Up to 24Meg Download (depends on distance from exchange)
Up to 1.3Meg Upload (same as above)
No packet shaping (torrents and usenet go at the same speed as everything else)
fair use policy only kicks in after 500Gb, and even then they only warn the first few times.

Alternativly if you can't get Be try ukonline, they used to be the best for speed and service but then got bought by Rupert Murdoch and sky so now I won't buy from them.