22lr -inexpensive, fun, effective in several platforms
30-30 -comparatively inexpensive, fun and rifles that shoot it are among my favorites.
30-06 -About as versatile as they make. Effective on a broad spectrum of game animals. Great bolt, pump and auto platforms
45-70 -Tops for grin factor, VERY effective on critters even at blackpowder levels, fun to shoot.
I can't decided on the fifth... Probably a pistol caliber in a carbine.