We've been with TalkTalk since Dec 2007, and had no real problems at all. Normally get 5-6MB* broadband (about 1.5mls from exchange), with WiFi (D-Link modem), plus free w/e and evening calls (including international, and line rental) for £16.50. With the calls we pay for, the grand monthly total is less than £22/mth all in.
*edit - just done speedtest.net and got 6.95 MBps DL 0.8Mbps UL. Fastest I've seen it.
Before we went Wifi our wired BB modem, developed a fault & had to be restarted everytime connection was attempted. I mentioned this on their forum, and was sent a new modem to replace it the next day.
Our 18mth contract expired, but we've stayed with them. If it ain't broke... I suppose there are horror stories with every provider.