The end tanks on the radiator are plastic, and if you live in an area with harsh weather, they eventually crack. I'd guess it's due to the repeated cycling between temperature extremes. I recently had to replace mine due to this. You'll see coolant leaking down and dripping off of the black plastic tank if that is the case.
A few years after I bought the car, the water pump bearings also started to go bad and leaking began in that area.
My bet is on your end tanks and not a hose.
Lane [ lane (at) evilplastic.com ]