Re: Picking some guns...
I agree with Another Scott...Take a class. If not two, for the different types of firearms you mentioned. Shooting a rifle != shooting a pistol.
You also should be able to go down to $YOUR_LOCAL_GUN_SHOP and try out their rental guns there. I know mine here in IL do that...So long as you have a valid FOID (Firearm Owner's ID) card.
That being said, I love my [link|http://www.glock.com/g35.htm|Glock .40 caliber semi-auto]. I don't get to take it out enough.
I'm only 5-10, so I felt that the .40 was enough; both .45's I tried felt like overkill, if you will. I squeeze shots two at a time anyway, and 2 from a .40 is enough to stop an intruder. Your little lady might think that the .40's a bit much. In that case, I would suggest the [link|http://www.glock.com/10.htm|10mm] or [link|http://www.glock.com/9x19.htm|9mm] pistols. My brother has a 9mm (I think the [link|http://www.glock.com/g17l.htm|G17L]), and he likes it. I find it a bit under-powered. If I want to stop an intruder from abusing me/my GF/her kids, then I want something I *KNOW* can stop 'em (tempered by my feelings of what's too powerful -- which is why I have the .40 instead of the .45.)
One thing that you'll need to know about Glock firearms is that there is *no external safety*. If your hand is positioned correctly and you squeeze the trigger, it *WILL* fire. There's no button to push on the side of the fun. No handle-pressure-mechanism. If you squeeze it, it will fire. The only safety is on the trigger itself. If you depress that little catch on the trigger and continue squeezing, off it goes. Some people have a serious problem with this. I personally like it, as it's one less thing to fuck with when I'm awakened by an intruder at 3am.
Update: [link|http://www.glock.com/_safe_action_.htm|More info about Glock's Safe Action System] and [link|http://www.glock.com/trigger_safety.htm|their trigger safety mechanism].
