If there were one right answer, we would all agree.
Question: are you willing to change the way you dress in order to carry? If so, no reason not to carry a full-size pistol. You'll need a QUALITY IWB holster (like a Milt Sparks Versa-Max) and a stiff, quality gunbelt to do that comfortably.
The only problem is you have to be able to dress so folks never seen the side & back of your belt. Blazers, sport coats, sweaters, vests, untucked shirts (even t-shirts) all work. A tucked-in dress shirt with nothing over it does not work.
If you are willing to carry full-sized, then the choices are too numerous to discuss. I like the BHP 'cuz I like SA cocked & locked. And it is flat & easy to carry.
If you're willing to change your dress so you can carry IWB, and you are a cheapskate like me, then a compact 9mm might be best. They can carry OK in cheaper holster/belt combos. Your choices include mini-Glocks, Kahr's and Kel-Tec P-11. Some bigger people that dress in pants with large pockets can carry these in a pocket holster. I can't.
If you can't change the way you dress, then you might be able to carry a compact 9mm in Thunderware or equivalent "pubic pouch", or Pager Pal "all the way inside the belt".
Or you're stuck with a mouse gun in a pocket holster. Sorry, no more 9mm. .32 or under. You can carry that setup anywhere you can wear pants. Kel-Tec P-32 or Beretta Tomcat/Jetfire, NAA Guardian, Seacamp, etc.