.38spl
Dead reliable, fits in the pocket of anything I wear including gym shorts.
Please, for the love of all that is holy, don't carry on your ankle. I don't know if I can think of a worse way to carry. Better than NOT carrying, but man, it's terrible. Takes too long to get to. A person can cover a 15 foot distance well before you can draw a pistol off your ankle. Bad juju.
EDIT: Just saw this one for sale. Highly recommend.