It is a real mess. We are in Band E, but there are only two of us left, so our cost to the council is far less than a family in a Band B or C property who will use far more services. Linking the tax to what a drive-by assessor of your property deemed to be its value 35 years ago is nonsense - nobody's use of council services is linked to the value of their house, and anyway, property values have shifted since streets were last assessed.
I don't mind paying for services I don't use, as others do use them and it's swings and roundabouts, but I do object to paying the same as a household of six, particularly when there is a discount for single people which recognises that the fewer people at an address, the less they spend.
It gets even more complicated where discounts are concerned - eg if a group of students live together they pay no council tax, but as soon as one of them graduates or leaves their course the whole household is liable to pay.
I don't know what would be fair, really. Things do have to be paid for, and in the long run it is fairer if we all pay to make services available to those who want or need them, but neither house value nor household size seems a sensible basis for determining the charge. Maybe individual bills would make sense, with discounts where applicable, or a ring-fenced addition to income tax? That could be shared amongst councils on a per capita basis, so that people in less wealthy areas don't suffer from the 'double whammy' of getting fewer services from a cash-strapped council.