I was thinking:
Dear Boss,
Than you for letting me be a slave and doing the work of 5 people with less pay than the receptionist. I sincerely enjoyed the time I spent here being the "buck" for all the incompetant people and enjoy picking up the pieces when they left.
I have also enjoyed being unable to call on any form of support for systems I am not authorised to administer, but am expected to anyway and also enjoy the blame that goes with that.
I would like to take this oppertunity to also thank your daughter for the excellent 'Christmas present' which has made my stay here very enjoyable. I might comment that the boardroom table is of excellent build quality and comfortably takes the weight of two adults.
Anyway I digress. I would appreciate it if we could forgo the contractual obligation of notice period and you would do me the honour of putting me on gardening leave for the duration.
I will gladly assist attempts to recruit a new person, however, you may want to make the job offer a bit more attractive than peasant or slave as I believe that slaves don't expect to get paid.
Yours sincerely