1). .30/30 Win (fun, functional)
2). .338 Win Mag (with handloads, becomes very versitle)
3). .375 H&H (again, handloads and versitility)
Each of these will nicely overlap each other, allowing for small game hunting (head-shots are a must) up to taking out that willey M1 battle tank that I've been stalking for two years...