I'm going to post a 2nd choice here after finding that I agree with many previous posters that chose a K framed, duty size .357. In my case, I have several but the M-66 Smith, a stainless steel beauty with a buttery DA trigger, makes the most sense. While we're at it, chose it with a 4 inch barrel too...that'll enhance the accuracy, & the weight will absorb more recoil; then learn to dress around it for concealed carry.
Simplicity of manual of arms: Revolvers rule in this category. Just pull the trigger. No magazine worries, no feeding problems, no 'limp wristing' problems if your grip is not quite right, no safety to engage/disengage etc. In most cases, new shooters will require far less training to operate the gun, but may/will require more to attain good/great ability. But for close in, 3-8 yard or less defensive shooting, a wheel gun'll do nicely.
Targets, and/or training with relatively new shooters....wadcutters at ~750 fps are easier to master while learning and lots of fun later on.
Night stand: .357 Magnum medium loads...maybe home crafted to the old 'FBI' standard of 950 fps...140 gr JHP's will shorten the recoil recovery time and give good penetration with out 'over doing it'.
Concealed carry: Replace the Smith target stocks with Jerry Mikulek's DA grips and load it up with 135 gr Speer Gold Dots of .38 Special +P persuasion, (great defensive loads universally known for their effectiveness). The Special's shorter case length enhances ejection and also makes reloading easier. And finally, their reduced recoil allows quicker 2nd shots if necessary.
Round the farm: Full house .357 Magnum LSWC's for unruly or sick stock that will also due for deer inside 50 yds with accurate placement.
Availability: Both guns and loads are found in nearly every crossroad gun shop except in times of panic buying.
Here's one on my son's hip...an ex-LEO veteren...in a rig we use often. And another in my usual carry position with Mikulek grips...a real boon to DA control and accuracy.
Best regards, Rod