1. 30-06, I'm old school like that I guess and it gets my vote as the best all around cartridge of all time.
2. .22 It should be a rule that everyone owns a 22
3. .243 From the little the the mid-size game this cartridge can get the job done.
1. .45ACP Come on, it's a 45!
2. .357 My revolver just loves to sling magnums.
3. .22 See above
If I could only have 3 period I'd have to say the 30-06, the .45ACP, and a .22.