I've tried carrying my .357 S&W but it is too big for most clothing save my carry jacket which can carry most anything but is only useful in cold weather.
My S&W model 39 9mm with a simple inside the trouser holster is my normal carry and with the ammunition carried I feel I'm fairly well armed without being weighed down or obvious that I'm carrying.
One of the best CONCEALED HANDGUNS ever manufactured; a Kimber Super Carry Pro with .45 caliber Hornady Critical Defense in the pipe, surrounded by Mitch Rosin Leather on the strong side and a spare KimPro Tac-Mag surrounded by the same Leather on the weak side; as well as a Kel-Tec P32 clipped to my strong side rear pocket.
XDs - XD40 Service; XD40SC; or XD45C. Used to be always the SC. But couldn't stand not having a 45 so bought the XD45C a while back and that's what I carry mostly now. I replaced the kydex shell on my M-TAC with the slide version so now any of them fit nicely. Carrying the 45 vs the 40 is nearly no difference at all; except of course the feeling of being "better prepared".
For a more concealable semi-auto I'd suggest a PPK/S in .380 ACP with Hornaday's new 'Critical Defense' ammo. I've test fired this ammo into wet phone books and got penetration half way into the second book with picture perfect expansion. There are slso a couple of smaller .45 ACP pistols on the market which I've never fired but I suspect the recoil would be prodigeous making a second shot (if necessary) a little "iffy."
Ruger SR40C on either an OWB Tagua Leather Quickdraw Holster or Crossbreed Supertuck Deluxe IWB Holster. Sometimes I also carry my Smith and Wesson Bodyguard 380 in my pocket. Am waiting on an ankle holster to arrive so I can wear my Beretta Storm PX4 Subcompact on ankle as backup.