I bet most of you know that ING  doesn’t have the best interest rate, but did you know that there are five other banks that match or exceed ING’s piddly 3.15%? Current top dog is Presidential Savings with a 3.75% APY with their Checking account in second with a 3.5% APY (Emigrant Direct  tied for second with a savings of 3.5%). The best list of updated interest rates I know of is Flexo’s at Consumerism Commentary , he keeps that list as up to date as possible and it contains other useful information, such as Quicken and MS Money accessibility.
My personal experience with online banks is limited to ING and Emigrant Direct, I discussed both as emergency fund safe houses  a while back and an alternative to Certificates of Deposit. Personally, I go with the higher interest rate but ING is the better known name and has a much prettier interface. Emigrant is very austere which lead many to think it’s not reliable, which I believe is a mistake. A deposit into Emigrant Direct takes approximately five business days to clear while a withdrawal takes a mere two days (I withdrew at 1am once, it cleared within 48 hours). With ING, a deposit takes five days to clear and a withdrawal takes anywhere from two to three days.
ING can offer a lower interest rate because it already has a sizable customer base; it no longer uses that interest rate as a hook. It will be quite some time before ING catches up to Emigrant, if that ever happens. For those of you thinking ING will match Emigrant, I suggest you make the switch to Emigrant because that’s a race ING won’t win unless a major shift in market share occurs.
ING Direct has a referral program, if you are interested in picking up $25 (I get $10) for opening an account, drop me an email .