Hello,
I think those who've said to hold, and test fire if possible, any gun you're interested in are giving good advice. I only buy guns bind when I already have some idea what I'm getting (have several 1911's so I know the grip feel and know it isn't like to change greatly between manufacturers). That being said, and for the uses you've specified, I wouldn't recommend any of the above pistols. Personally, I am not a fan of striker fired, no safety pistols (Glock, XD, M&P). This stems mostly from the extensive training required to carry one in a safe manner with a round chambered. Also, for a home defense gun 9MM, .357 sig, 38 super and the other high velocity ammo are, in my opinion once again, too hot a round to be used indoors with the expectation of a soft target (read human body) stopping the round. Over penetration through the target and up to several walls is something you have to consider when there are children in the house, neighbors in close proximity or when all living areas are on the same floor.
I wouldn't want the bullet meant for the bad guy to also take out my wife, child, neighbor or even the dog/cat (realizing these aren't likely scenarios, but still being possible is more than I would accept). .45 is big, slow and cumbersome but hits like 2x4 to the chest and even a bad shot is still gonna put the target down or atleast limit capacity to act (broken bones and internal bleeding will definitely decrease the motivation of even the most determined home invader).
This said, if you want a range pistol I would go with those recommending 1911's as that is what
I shoot well. You can get a 9MM or .40 cal if you would prefer cheaper ammo and still have the trigger and accuracy of the 1911 platform (Rock Island Armory, Citadel, even springfield armory make 9MM for a good priced entry if that is what you prefer. Those brands also offer extremely nice .45 versions at entry level pricing and up, springfield especially). If you feel a defensive handgun is something you
MUST have, I recomend some type of DA revolver for the lower price range. It never jams, has a consistent double action trigger (allowing that little extra time to determine targets compared to SAO guns [back to having a wife, kids, dog in the house]) and can be had with good quality in the under $500 range, especially if you don't mind buying a used gun. Also, something like a .357 gives you the option of .38 special for cheap range time and introducing new shooters with decreased recoil and still keeping the .357 HP for defense.
My personal preference is for a defensive shotgun. Doesn't need to be anything special from your normal field gun, but a shorter barrel would be more manageable in tight quarters. Longer sight radius, can use any multitude of ammo from 00Buck to rock salt depending on situation and intent, mountable accessories like lights and optics and substantially reduced risk of over penetration of target. Also provides for the use of less than lethal rounds like beanbag or rubber bullet rounds (broken ribs or bruised chest at worst as long as shooter knows when/where to shoot). As I have said above these are just my opinions and should be considered as such. Final decision should still be based on what you are comfortable with. I apologise for writing a book, sometimes I just get to typing just to hear myself
James