EDIT: See the direct link in my reply below -
(the link on the right takes you to the home page - even though its the same as the link in my reply not sure whats going on)
Nationwide currently have a offer (for both existing and new customers), where if you transfer your direct-debits/standing orders from another bank to them, they will credit your account with 75 pounds.
For existing customers, logon to internet banking and choose the switching service option.
For new customers, open a new account and choose the "switch all direct debits" option.
Remember, you need to switch ALL your direct debits, and not just a few from your old bank to get this offer.
Also, this expires on 5th March!
Easy way to get 75 pounds just for switching - works for existing and new!