Now you are asking
Trouble is "best value" probably means a lot to different people. I'd hate to single out a specific ISP.
I'd steer clear of Tiscali only cos they seem to be going down the bad routes of ntl threatening customers, etc. Wanadoo are probably not a lot better. Bulldog have had a lot of bad press too. AOL can be quite good, if you like all the extra software, kiddie protection etc, but then you are often tied to their email client.
I suppose you are looking at ISPs like Plusnet, Nildram, etc, but many of these are also going down the capping route