I carry the largest caliber/capacity, that I can for the occasion. My guaranteed everyday carry is a full size Glock 34/35/41 (9/40/45) with a Streamlight TLR1-HL or a S&W Bodyguard 380, if I need something really concealable. I have several other handguns that I carry occasionally as well.
45ACP. It just feels right and goes where I want it to go whether it's from my 1911's or the XDs.
But 9mm is a close 2nd, getting slightly more carry time these days.
More than comfortable/confident/proficient with both, but the 45 just feels like being on autopilot.
Woods gun is a 44mag during hunting seasons, one of the above any other time.
When ever I got Pants on, my Ruger LCP in .380 is in my pocket. For years my main carry gun was a Glock 26, but lately I have been carrying a Sig P365, both 9mm. Sometimes I will switch things up, and carry a .45 1911.
In the woods, usually a shorter barrel .44 mag. Picked up a snubby S&W model 69 a few years ago, and it's become a favorite .44 for the woods.