I use ntlworld.
The price has just gone up, to 14.99 UKP /month from 9.99 UKP <grumble, grumble>.
This gives 24/7 access via freecall number as well as 14.99 UKP worth of phone calls.
There's a one-off 10 quid charge for a phone adapter that divert calls through the NTL network.
Calls charges over 14.99 in value are charged at NTL's rates ~ 1 p/min less than BT / plus 3.5 p connection. National calls are charged at local rates.
I used to connect at 44k (max 48) but since Xmas the line speed has dropped to about 38k (max 42).