I use Force9 lona and can't fault their service.
They are currently doing a "free activation" and free hardware offer at £24.99 a month. Actually they just increased the monthly price a bit to include the activation charge. Does BT give you the modem?, if not the free month might not be such a good deal
I pay £21.99 but had to pay an activation charge. Best bit is the 250mb webspace. If you don't need the webspace there may be better offers around.
You can see more info
HERENo doubt Simon et all will be here soon to recommend Pipex so they get their free month!
(I would have gone with Pipex but needed the webspace!)
You might be good looking at ISPreview - but I see you already have posted a link on another thread
Good luck !
DJ
PS - Now I have broadband, even though the increased monthly charge - I wouldn't go back to normal dial up
EDIT: Just had a quick look on ISPreview, Force9 and Plusnet are the same company just a different branding. So use plusnet as a comparison against other products.
PPS! - If you do want to go with Force9, let me know cos I'll give you a referal link. (doh - I'm getting like Simon
)