my current CCW is a Sig 239 but I change weapons almost every day/week, if you carry now a Glock 23 a good choice will be the Glock 27 same mags from the 23 etc. but I carry an XDs in .45 ACP also, small package with .45 power.
I've been carrying a Sig 239 .357Sig for years. I have a new G19 that I'll probably start carrying when I get my holster from http://www.rmholsters.com/ I have one ordered.
I was stunned to see that the 3" barrel sig P938 that I carry has more energy than the 5" extended/threaded barrel Glock 17's. Note also the G4 G17 matches the G3 G17 TB, The Gen4 G17 gained NOTHING from the addition of a threaded barrel. All these shot on same day with same box of ammo on same chronograph.
And one more big note. Those of you who carry a .380. Make SURE to carry good ammunition in them. The Hornady XTP bullet has dominated the testing and is all I would carry in one if I were you. I personally witnessed a shot indoors of a G42 with critical defense PDX1 and it did NOT penetrate 2 layers of drywall. Actually barely cracked the second layer. The bullet expands too quickly and dumps all of it's energy too soon IMO.