@stevezero, this is going to be a hot topic so what I type here will probably get me flamed
Bottom line to carry or house gun: use what you're comfortable with and most importantly what you've trained with. If you're not going to train you shouldn't even have a gun for defensive purposes.
My opinion:
Revolvers went out about the time of Dirty Harry. With the reliability of glocks/springfields/SIGs there is no reason to sacrifice capacity for a "percieved" reliability of a revolver. It's like bringing a knife to a gun fight. DOJ crime statistics put the average number of home invaders at 4. So if you want to roll with your 6 shot wheel gun that's fine. Just don't miss a single head shot.
If I could only own one gun it would be the Glock 19. Small enough to carry, big enough to get you out of a serious fire fight. Lots and lots of aftermarket support, and it goes bang! every time you pull the trigger. Get yourself a fingerprint safe for the bed side and you're good to go in the house. I find it's easiest to carry the 19 with my body shape/size using IWB appendix carry. It conceals under most tshirts and button ups. Check out T-Rex arms for their holsters, the side car is what I use.
If you like the 19 you can go up or down to the model 17 or 43 and effectively have the same gun operationally just in a different size, which someone above mentioned the benefits of this.
I also carry a Springfield armory XDS in .45 for the days when I need to conceal something smaller based on clothing choices. I carry this at the 3 o'clock position IWB.
As far as caliber is concerned; with the advances in ammunition unless you shoot .45 better than 9mm, you should go with 9mm. Capacity is undervalued in the GI JOE world of internet generals. Size and weight also becomes an issue when you're carrying with regards to your belts and your pants. And if .380 were even in this conversation the military/police would use it, but because it shouldn't even be in this discussion completely ignore this as a possible choice unless you absolutely need a pocket pistol as a last resort. (If you're wearing a suit downtown all day this might be your only/best option).
There are a lot of really great youtube resources for gun reviews, 9mm vs .45, carry styles out there. Do some research and go try out lots of guns before you buy one. Once you get over the fact that the barrel is pointed at your crotch instead of your hip appendix carry is pretty good, and you can access it from the driver seat.
Again, if I could only own one gun it would be the Glock 19, but try the Springfield Armory XDM 9mm if you like the grip angle of a 1911 as they're the same. If you have any questions feel free to PM me.