There's an obscure deal (tune out if your county doesn't allow for flat
rates in lieu of the 1.5-2.5% convenience fee ripoff payment for miles)
regarding Discover and the City and County of San Francisco, who
must have some sort of sweetheart arrangement going on here...

Although if you pay property taxes *online*, there's the 2%+ fee
that makes you actually pay for points/miles, try the walk-up
window for a maximum $35 charge, but only using Discover.

For a typical Frisco homeowner, the savings can be non-trivial.
Here are the particulars -- only the Over-the-Counter rates are
worth it:

http://www.sfgov.org/site/treasurer_page.asp?id=13395

I did this starting 2007 on a 0% APR Miles card; that year one could
get an extra 5% per annum by banking the balance for 12-18 months,
while collecting the miles bonus, so that was money back.

This year, there's not much advantage playing the 0% APR game
but there is the double-points Escape by Discover card with a 25,000
point bonus to boot.

Using the City Hall walkup window on a multi-thousand dollar
tax bill can pay back, unlike the 2% "convenience" fee offers where
you'd lose big the other direction! So, does City Hall eat the typical
"retailer" fee on this Discover deal, or does Discover, by paying
San Francisco for the privilege?