If you need a good carry gun, I would sugest any of the many good 9mm or 380 compacts. A Smith J-frame or the Ruger LCR would be wonderful as well.
What about thickness differences? I too am in the market for a compact or sub-compact .45. Four that I am looking at would be the G36, XD45c, Kimber Ultra Carry II, and SA Loaded Micro compact. Kimber and SA are definitely at a disadvantage from a price point. But looking at the widths, the thinnest is the XD45c, which is odd because I believe it is the only double stack in the group. I would have expected it to be the thickest. I'm finding a range of about a 1/4 of an inch (XD45c = 1.125", G36 = 1.13", SA micro = 1.365"). I definitely want a thinner pistol to help with concealment, but how much do you think a 1/4" will make?