My LCP (.380), my PT111 (9mm) or my snubby (.38).
If I'm going out to dinner, a large public gathering or similar then I carry my 24/7 (.40) which is the largest gun that I pack (my 1911 lives at home). It's the least comfortable to carry (sitting is almost painful with an IWB holser) but this gun is a tack driver and powerful enough to get the BG's serious attention.
I voted 9mm because I carry it just a tad more often.
