Some good suggestions have been offered.
Beretta PX-4 (under $500)
Beretta 92FS (Mid-$500)
Beretta M9 (Low $500) - a military version of the 92FS.
CZ-75B 9mm ~$500
Rock Island 1911 9mm - (About $400)
Rock Island 1911 .45ACP (About $415)
Springfield XD 9mm (Under $500)
You really need to paw and handle a handgun before deciding to purchase. A lot of things might look good on paper or in color photos, but not feel right in the hand. Handle pistols and look for one that is a good fit to your hand.
If you want high capacity, strike the 1911 models from the list. The PX-4 is a nice gun but for me, the rounded edges and shape don't feel right in the hand. That's a personal opinion.
When looking for a pistol, for your purposes, I'd definitely select one with an external safety. That eliminates several brands or models, including Glocks, most new S&W pistols and the Springfield XD. As good as those guns are, if it will be in a home with non-shooters (wife & kids) an external safety is a must.
For the uninitiated, revolvers are simpler to work because you provide all the muscle power for each step. There's one button the side of the gun for reloading. Some pistols, however, have multiple levers on them which can cause confusion for the unfamiliar. The pistol also automatically performs several operations after firing to eject and reload the chamber. This can bother some shooters.
In a revolver, you should be able to find an excellent, previously owned .38 or .357 magnum for under $500. Cosmetic flaws from use or handling will drop the price somewhat. The .357 Magnum is simply a longer, more powerful .38 Special so it will shoot the .38 Special. The .38 cannot chamber the longer .357 however.
Right now, 9mm ammunition is relatively cheap. The .38 Special is comparable in cost when we're talking paper-punching ammo. When it comes to serious personal defense ammo, the terminal effects of .38 Special +P vs. 9mm are going to be very similar. Using the .357 for home defense is a bit of overkill, IMO.
I'm approaching 60 now, and old age takes its toll. I find the sights on my Beretta 92FS are easier to use than most other brands. I resisted the "large capacity" pistols for years due to their bulk and weight. The 92FS, itself is a large pistol that sits low in the hand, isn't too heavy and shoots very precisely. It has an external safety and a long double-action first trigger pull and a lighter pull subsequently.
BillCA in CA (Unfortunately)