Hi, we were with Orange originally Freeserve for many years and with BT for the line and phone, but just over 12 months ago switched to the Post Office for line rental calls and Broadband extra. We find all of it cheaper by quite a bit and the broadband goes at nearly 3 times the speed it did when with Orange. BT seem to add on bits and bobs for the way you pay but the Post Office just give one price. Hopes this helps.
By the way when you tell Orange you want to leave them they will offer you your internet for about a third of what you pay them at the moment. They have with everyone I know.