The initial 7k miles from BankDirect come very quickly. You need to decide whether its worthwhile to continue keeping the account open.

If you value AA miles at X cpm, then keeping money at BankDirect effectively gives you a 1.2X% APY checking. Apart from the 2.5k minimum balance there is no other requirement to get the miles. The interest rate is also constant unless your valuation of AA miles changes.

There are other checking/savings accounts which give you a slightly better rate. There are also rewards checking accounts which give you as high as 4% APY. However, these also come with monthly requirements like 10-15 debit card transactions, direct deposit, e-statements and a few billpays. Moreover, they only pay these interest rates for balances upto 25K or even less. You also need to worry rate chasing.

Check out the following links. You can also find historic interest rates by clicking on the + icon next to each bank:
http://www.depositaccounts.com/checking/
http://www.depositaccounts.com/check...-accounts.html
http://www.depositaccounts.com/savings/