My "go to gun"? CZ75B .40 S&W duo-tone (stainless frame, park/blued slide). Very accurate, never fails to run and keeps running.. Not uncommon to shoot 200-300 rounds through it nearly every weekend.
The absolute, never part with, pass to the kids, pry from my cold dead hands gun?
Actually, it's two:
1890 Winchester pump in 22WRF. Bought new by my great-grandfather in Tennessee in 1920 (have the paperwork), still shoot and fairly accurate.
The other is an Arisaka mod. 44 calvary carbine made in about 1928 in 6.5X50 Jap. Brought back by other grandfather. I got ammo, know where it shoots and shoot it often. Real loud and a great conversation starter at the range.