Just for anyone who missed this in the budget, be careful if you are in the market for buying a larger 2001 thru 2006 vehicle.
The emissions banding system was introduced in 2001, then extended in 2006, with the higher categories created at that time being applicable
only to new vehicles from that date onward. However, in this most recent budget the Chancellor announced that from next year vehicles back to 2001 will come under the extended banding, so tax rates are set to soar for some vehicles.
The good news is that if drive one of those tiny bumper cars, models back to 2001 will also come under the revised banding so you may end up paying less.
Summary of the proposed changes here:
http://www.direct.gov.uk/en/Nl1/Newsroom/Budget2008/DG_073093