I recently spoke with a loan officer at the bank I've been with for years. My lowest score is 635 and that's because the only tradeline I have is not reporting payment or balance history to this particular CRA at all which, I've been told by the creditor, is being resolved and should be showing within 30 days.
My highest score is 685. The loan officer said this is a very good score when it comes to getting a loan. He said that, granted, your absolute best interest rate will come with ANY score over 720+. At my bank anyway, it doesn't matter if you're 720 or 820, you get the same top rate according to him. Unfortunately, he advised me that the CRA with my lowest score is the one that they use to approve their loans. :-( Wouldn't you know it!
He told me that they approve loans in the upper 500's - depending on actual credit history, however, at a much higher rate. He said that with my scores, I wouldn't necessarily need any money down for a home and since I'm a first time homebuyer, I qualify for a variety of "down payment" programs anyway. He also said that if I have the payments automatically withdrawn from my checking account with them, then they knock points off of the interest rate. Nice bonus for going with your old faithful bank.
If you have a checking or savings account, just call and talk with a loan officer at your bank. Ask them as many questions as you can think of. They're more than willing to offer you advice - at least my bank is, especially if they think they can talk you into taking out a loan with them.