Ally Bank (http://www.allybank.com) is near the top. I personally use ING Direct (http://www.ingdirect.com) not the highest but stable and near the top.

Very frequently, web only accounts will offer higher interest. If you are looking for a savings account, where you will be transfering in and out from your checking - or getting direct deposit, you can't go wrong with a web-only account from a well-respected and stable instituion.

Given that a lot of banks are in rough water right now, you should carefully research the online accounts in which you are interested.