From what you posted in your list a Sig 239 in 9mm should work really well for her, of course this is all speculation since I don't know your wife. The 239 is very easy to shoot and very light recoil, easy to rack the slide which is an issue for some women, grip isn't too large so it should accommodate smaller hands, comes standard with night sights, decent capacity and option of extended mags, gun is very accurate and naturally pointing. I plan to pick one up myself eventually.
I notice you listed the SR9C, and although it is a great gun and I carried one for close to 2 years, that sucker has one of the hardest slides to rack out of any semi-auto I picked up. The reason is the gun has a dual recoil spring, which although is great for soaking up recoil, it makes the slide very heavy and hard to rack. Was never an issue for me personally, but some women have trouble finding guns that they can reliably rack the slide on, just something to watch out for.
I also owned both a S&W 60 and 640 which you have on the list. Snub revolvers take alot of practice to become proficient with. I carried S&W J frames for close to 3 years, and even though I became pretty proficient with them, I was never satisfied with the accuracy I was getting, especially when the gun only holds 5 rounds. Snub revolvers don't have buttery smooth triggers like their larger counterparts due to having to use a heavy coil spring vs a leaf spring you see in larger revolvers. Throw in the very short sight radius and you have yourself a gun that's just not very easy to shoot without putting in the time for practice. If your wife is willing to put in the range time then go all for it, but if this is a gun she wont be shooting too often I would stray away from the snub revolver.
Last edited by Dragline45; May 1, 2013 at 12:16 AM.