Compact... with the grip extension and a 16 round magazine, the only difference between that and the full size is 1/2" in barrel and sight length... BUT you can carry it much more discreetly than the full size by using the regular compact magazines. In other words, it's easier to add a full-cap mag to a compact than cut 1/2" off the barrel and 1" off the grip of a full size.
I've carried my full-size in .40, it's concealable, but if I had to choose one, it'd definitely be the compact.