I agree with Icarus only if you pay the bill in full during the first statement period and you do not use a credit card which balance averages over two statements (the latest ripoff tactic of the credit card industry).
Also depends on the travel market you live in and go to. Here in the NY region, if I were going to Florida, miles are worth about $5 per 1,000 due to the great competition and many flights.
If you need to fly from Duluth (no offense!) to St. Maarten each year, the miles are worth MUCH more per 1,000, sometimes as much as $20+ per 1,000.
PS. Talk with your tax preparer to see whether the fee charged to pay by credit card is a tax deduction since it's not really a finance charge (not deductable) but a fee specific to making the tax payment. That would really sweeten the deal as real estate taxes paid are a deduction (if you itemize).