I standardize country, especially US and Canada. If any Lead is created with any of a variety of ways you can put US, the system is triggered to change it to the two-digit form.
Another one we have is for Customers. Since it is incredibly difficult, and important, to not blast to existing customers, I take the email naming convention and the generic form of a company name and use them in trigger campaigns. If a Lead is created and matches the criteria, a checkbox titled "Potential Customer" is checked. It is just a way to slow down the rep and double check whether they are or not. Also, these folks are excluded from blasts until proven otherwise.