There are four that never fail to impress me: 30-06, 308, 270, and 7x57. If I were to choose amoung the four, it would be 7x57. It gets the job done, always, with less recoil and a nice flat trajectory. All the rest are simply boutique calibres to me

Yes, you can substitute 7mm-08 for 7x57 if you don't reload.
Honourable mention to 12 gauge (e.g. 870)... a rifled barrel sabot slug gun is a rifle to me, and mine works well to 150 yards with deadly accuracy. Of course, it doubles as a real shotgun, for whatever fowl you wish to hunt.
Left to Right:
12 Gauge 3" --(00 Buck)
30-06 Springfield --(180 grain soft point)
7mm Mauser / 7x57 --(173 grain soft point)
308 Winchester / 7.62x52 NATO --(165 grain SST)
7.62x39 Soviet --(123 grain, brass case, soft point)
7.62x39 Soviet --(123 grain, lacquered steel case, steel core FMJ)
22 LR --(40 grain lead round nose)