I own nearly 50 handguns.  My answer really depends on the situation in which I would need the gun. 

For concealed carry, I generally go with my Glock 23 (.40) and my Walther PPK/S (.380) as the back-up.

As far as a hands down favorite.  I have to go with my Beretta 92FS.  I've put close to 50,000 rounds through this gun, and of all the handguns I own, I am the most accurate and efficient with this gun.  It just fits me the best.  I have large hands and the bulk of the Beretta fits perfectly.  I come out of my SERPA holster quickly and onto target in an instant.  Tactical reloads are a breeze.  I like the weight of the trigger after the first round is fired.  The trigger is very light for rounds 2-16.

I know a lot of people aren't fans of the 9mm round, but it has better peneteration of soft tissue than a .40 or .45 ACP.  Placement of your rounds is the crucial factor.  Hits to center mass will be sufficient.

springfield xdm .40

Been competing the past three years with a S&W M&P 9mm.  Love the gun, of course i've tried a glock and a Berretta 92.  Those worked well and I liked 'em.

You mean 357 Sig right?

So far they seem ok. When you get the gun it comes with clips to use on the acp's. Two for holding six and two for holding two. They are kind of difficult to use. Apparently there is a tool that makes it much easier.

I mostly use it with .410 shells.  They are fun.

I have an ubertti 45 long cotl. it is so fun to shoot

having been on a army rifle competition team..(long ago)..i am naturally partial to the 1911..but still a rifleman at heart

I'm a 1911 fan, but for a carry gun id go would go with the sig p220. Shoots great reliable and you cant beat the power for a 45 acp