Just to offer a radically different answer from what you wanted:
Smith & Wesson 686
This is chambered in .357 Magnum and will certainly do the trick as a defensive weapon, while requiring less attention than a Glock, Sig, etc. You can load it up, and it'll fire reliably 5 years later.
The auto, while a phenomenal weapon, will require that you rotate magazines on a regular basis. While spring steel has improved, it will not take well to being compressed for years on end. An auto will also require more practice to be comfortable monkeying with safety, slide release, decocking lever etc.
A revolver lacks the capacity of an auto, but has simplicity and lack of hassle on its side.
Just a thought, now the answer you were looking for:
I think you should go shoot everything you are considering and buy what fits your hand and you shoot well. I have a Glock 23 that I shoot very well. You might not be able to hit the broad side of a barn with it, yet could spank me with something else. Ultimately, you'll be happy with any of the better pistols out there. Glock, Sig Sauer, Heckler & Koch are all great, can't-go-wrong guns.
Good luck, make sure it's something you enjoy shooting so you'll shoot more and get better at it.