Okay, some people gave more than one answer. lol.
As of this date:
For CCW - HK USP 9 Compact. Only modification is the nickel plated sear spring.
For nightstand/work-related stuff (gun shops or depending what security gig I pick up) is my MK25(P226). Mods are Gray Guns Flat Trigger, SRT trigger kit, and Wolff 17lbs hammer spring. It has a threaded barrel and sports a Surefire X300U.
Honorary mentions are the Glock 19 Gen 3, when I'm working with someone that carries the same guns for magazine interchangeable reasons.
FNX-45 Tactical FDE with the threaded barrel, Vortex optic, FDE Surefire X300U.