Be aware that leaving the AC fan on full time will increase the humidity level inside your house. Once the compressor cuts off, air blowing across the coils will transfer the moisture condensed on those coils (think of the moisture condensed on a glass of ice water) into your house. If you live in Arizona this might not be a problem, but it might be uncomfortable in the deep south.
Also, if your A/C unit and ducting are located inside a very hot attic area (like mine), leaving the fan running soon begins to blow not on moist air but moist and warm air into the house.
I say leave it off.