It pays to pay attention because banks are tweaking rates all the time. By Laura Cohn, Associate Editor March 12, 2010 For an extra layer of frosting on your cash cake, we have often recommended the (relatively) high-yield savings account at Ally Bank. In fact, we praised the Ally savings account in our December 2009 Best of Everything list, citing its competitive yield and lack of monthly fees or minimum-balance requirements. (Ally now touts our recommendation in its ads and on its Web site, www.ally.com.)There's just one problem -- Ally lowered its yield. At 1.44%, it's no longer the best you can get. That doesn't mean you should rush to take your money out. But it pays to pay attention because banks are tweaking rates all the time. Topping our latest list of highest-yielding deposit accounts are American Express Bank, Colorado Federal Savings Bank and NewDominionDirect.com, all yielding 1.5%. Of the three, American Express Bank is most versatile -- it has no minimum-balance requirement and no fees. To access your money, you need to link the Amex account to an outside bank account and transfer your funds. The other two accounts have more rules and hidden fees. You can boost the earnings on your cash even more by putting it into a high-yielding checking account at an online bank, community bank or credit union. (For the best deals, check www.bankrate.com and www.depositaccounts.com. For checking accounts, also try www.checkingfinder.com.) Those accounts often come with more rules, too. For example, Liberty Bank (www.bankliberty.com) recently advertised an "eSmart Checking" rate of 3.51%, but you need to make at least 15 purchases a month with your debit card and sign up for at least one direct deposit or automatic withdrawal.