Moved from Zen at £25pm for 1.5Mb to talk talk doubled my bandwidth (I live in the country quite a way from the exchange) and now get free evening and weekend calls and free broadband for £12pm as they have their equipment in the exchange.
With them too. Pay around £20 for unlimited local, national and international calls any time of the day and night as well as for the broadband. Not sure of exact speeds but I think it's ~2MB which is usually okay for what I'm doing. Customer service on their support forum is usually of a high standard, I don't bother with calling now.