I would have to conclude that if i could only have 1 it would be because of either economic reasons or Government intrusion. Therefore I would have to choose the .357 Magnum or the Rechambered .357 max.
The reasons would be.
Ammo availability, .38 special, 357mag or the super-charged 357max:
1.) .38 specials are available at super low cost and just about everywhere in the country, which offers the opportunity to practice a lot without waking the dead.
2.)The .357 mag cartridge is also readily available and offers good home protection as well as an affective close range deer round.
3.) The .357max brings the energy level to the point that just about any North American Game animal can be dispatched if the range is ethical.
The .30-30 would be my 2nd choice for many of the same reasons.
The .45-70 while very nice, it can be hard on the wallet for $$ conscience Handi-owners that don't reload.