First gun always is my Remington 341 Sportmaster .22LR, Bolt Action, 24" Barrel, Manufacture Date 1933. Rigged with a two point nylon military sling & Q.D. swivels. Open Sights. I've had it for 50 years, and have no problem using it either right or left handed. And from a rest, left handed, it will put out an accurate rate of fire about twice what the Warren Commission says can be done with a bolt action rifle. It carries easy slung, and a thousand rounds in a SAW pouch is packable. It's what I'm best with.
I do like my Glock 21, but I'd have to go with my S&W 500 Magnum. Only because it will certainly put down anything out there, and with all the oddball genetic science we have now, finding a T-Rex on your front lawn is not totally beyond the ream of possibility. The 500 can dispatch it, and I can go back to my coffee & reading my newspaper.