Personal finance columnist Eileen Ambrose has a story today that puts into perspective the Fed's big cut to its key short-term interest rate.

Quoting Greg McBride of Bankrate.com, she says folks with home equity lines of credit should see a drop in rates as early as next month:

The most creditworthy customers could see their rate drop 0.75 percentage points, the same as yesterday's cut in the Fed funds rate.

Higher-risk borrowers might see a quarter- or half-point cut, McBride says.

She notes that fixed-rate mortgages have "little to do with the federal funds rate" set by the Fed but instead track the 10-year Treasury bill, which reacts to economic expectations and inflation. (That's why mortgage rates have been falling steadily in recent weeks.) But you're more likely to see a Fed-related impact if you're considering -- or have -- an adjustable-rate mortgage:

Adjustable-rate mortgages for creditworthy borrowers are tied to the one-year Treasury bill. This short-term bond moves largely in expectation of where interest rates are headed in the next 12 months, McBride says.

So, as the Fed has cut rates in past months, the one-year Treasury bill has dropped. The rate fell from 5 percent in July to 2.7 percent now, McBride says.