I must answer with the 5 best "flexible" ranging calibers similar to those I really use--

22RF-plinking( I like the 17 calibers)
22-250-varmints( I use 223 to 243 to 25.06)
30.06-deer size critters(In reality I use from 7mm08 to 300 Mag)
375 H&H Mag-elk,moose & bigger(I use 338 to 35 Whelen to 416 to 458WM)
12 gauge Shotty for all the rest

Guess I have to many guns!!