I used virgin for a short time while I was between BT and NTL and was happy with service and my sister has been with them for years and she is not someone who puts up with anything that she is not happy with.
BT is as good as any for PAYG. However, click here The Plusnet Plus BB package is only £14.99 per month. If you pay a one off £11.75 they don`t tie you to a 12 month contract and you get free modem, activation and set up. Also their helpline is national rates. (Brilliant Service too) Is it really worth going for anytime on 56K at these prices?