Besides going to an instructor which is great advice, u can also go to a good gun shop and ask the seller about different guns and accessories, but b4 u buy 1 u should know everything about guns. I recommend Effective Handgun Defense by Frank James and Armed Response by David Kenik, also, the Pistol Guide and Revolver Guide by George Nonte. I wouldn't recommend a shotgun because it is harder to wield and handle because of its weight and size and there's also heavy recoil and the loud report u want to avoid, if only for practical reasons. A .38 is what u should probably get, cost being a factor, also, and a revolver is probably more advisable.
Also, I recommend 1st getting a lo vel double-action CO2 airgun, between 400 fps and 500 fps. These largely mimic firearms and u can use them in your dwelling and they provide good training.
As for safety, this is not really a concern as all modern guns are equipped with good safeties whether internal, as in revolvers, or external as in semi-autos. Proper handling, of course, is part of safety.
If looks are a factor, I could recommend several, but this is partly subjective.
There is also the availability factor. Here in Canada there used to be a wide variety of handguns available but now only a few semi-autos are available, 6 models in 3 makes, Ruger, CZ, and Kimber. I imagine, though, the situation is better in the States.