Taxmaster

Very possibly Moist von Lipwig's next assignment¹ as Vetinari sets about reforming Ankh-Morpork's public services and economic institutions as part of the groundwork for the Undertaking. The current post-holder is Mr. Creaser, but as he is now seventy-four and is in all probability a residual hangover from previous Patricianships which had different ideas as to how to run the city, it is highly likely that Vetinari will suggest he retires with all due civic honours to make way for a new incumbent.

¹ This might have been dealt with in more detail in a later book, Raising Taxes (rumoured as of October 2007), but...no.