I have changed my gas and electricity supplier and saved around £300 a year. I've also changed my broadband/phone and line rental package from a whopping £240 a quarter from BT to talk talk unlimited for an average over £38 a month all inclusive.
Also switched home insurance with a saving of £100 a year.
My electricity was with NPower and gas via British Gas. I moved over to EDF dual fuel on DD.
Broadband phone and line rental was with BT. I moved to talk talk, no line rental, unlimited upto 8Mb BB and free calls to 01,02 and 03 numbers, anytime. My monthly bill includes around £10 extra to mobiles.
Home insurance was with HSBC, we now have it with Tesco.
We have something in common although I have very little faith in price-comparison sites. I have been with British Gas, NPower and Atlantic and now in the process of transferring to OnLine Utilities for gas and electricity. Moved over to TalkTalk from BT a couple of years ago.