Micro, Small, Compact
I've had a Glock 26 & 27 for carry, but got rid of them. I currently have 3 regular carry guns - tiny pocket, regular pocket, and IWB.
They are: Ruger LCP - reliable and super tiny & light. .380 has enough oomph for most situations. (10% of the time). Just can't be beat if you need something that small.
M&P340 j-frame w/CT - ultra reliable, ultra light (13.3oz), plenty powerful (with .357s). The CT grips make it very, very simple and accurate to shoot, even thought it does pound the hand with hot loads. Hammerless DAO carries beautifully in the pocket. (80% of the time)
My newest, Sig Sauer P239 (replaced a Glock 26). Single stack (thin for carry), DA/SA (my favorite action for carry - no manual safety to fiddle with, but the longer, heavier first pull makes me feel more comfortable than Glock-esque triggers), ultra-reliable reputation (however, I've had problems, but they are hopefully fixed now), super accurate and actually fun to shoot. (used 10% of the time for now, but it's so new, that will only go up, especially when cooler weather rolls around).
The Sig is newest and of course my favorite at the moment, but it's hard to beat the j-frame!
My goal was to get the best weapon for each of these carry sizes. For me, I am hopefully there (finally). I also have a Kahr P9 that I've used while the P239 was in the shop. It's a really fine piece, too, but I'll stick with the Sig assuming it runs 100% now.