Another option is an I Bond from the Treasury. It's current return is 1.48%, but it's return depends on inflation:
Each I Bond has a fixed interest rate component, determined at the time of purchase (currently 0%). It is then added to the inflation rate (updated every 6 months for your I Bond) to determine the overall interest rate of your I Bond.
However, you can only cash in an I Bond from at least 1 year after time of purchase. Redeeming between 1-5 years from purchase incurs a penalty of the last 3 months of interest. After 5 years, there's no penalty to redeem.
You can only buy $10k of I Bonds a year (another $5000 if you overpay your taxes and get your refund as an I Bond)
Obviously, since the interest rate is not as good as a rewards checking account (typically 3-4%), if you're willing to play the game then that will give a better return. Also, because of that 1 year waiting period, if you want to do this you'll have to shift your emergency fund to I Bonds gradually.
Also, an easy way that I have read about (but not executed myself) to meet the 10-12 debit transactions per month on your rewards checking account is to load that money onto an Amex Serve (free to do online debit loads) and then use that to pay bills (such as your credit card, mortgage, etc). You can automate Serve loads to either daily, weekly, or monthly. So just load a dollar every day or something.