The pistol I find best suited for my deep concealment needs is my Glock 23 in a trimmed and canted kholster. It won't print in a casual t-shirt or dress shirt.
Long time .38 Special user in various configurations. Borrowed a Keltec .380 a while back. Liked it alot but not as much as the LCP.
Now the Ruger LCP goes out the door more often than anything because it's so easy to carry and conceal. Deep concealment with some degree of comfort is my goal.