I'll go along with Chris Hayes, but with the addition of .38/.357 and 5.56. 9mm is for daily carry in subcompact pistols, usually a Shield Pus or X or S&W 3913. 10mm is just for all-around effectiveness over a wider range of needs in a 1911 or S&W 1006. The .45 ACP is for use in my 1911s and S&W Model 22 or 3rd gen S&Ws. I currently own no .40s. The .38/.357 is for my S&W revolvers in the J, K and L frames, as well as a Marlin Model lever gun. .22 is for general rifle plinking, and 5.56 is for my AR. Others I use less frequently include .30-30, .30 carbine and 12 gauge shotgun.
As a rule, I shoot most of my guns a few times a year, but the primary carry pieces are the 9mm pistols and the .38/.357 revolvers.