Good question , I think if I had to choose one, and only one it would be .25 . Having, .177, .22, 25, .30, and 35. The .25 for me falls right in the middle of perfect, sure the .177 is best for plinking all day and on the cheap, and sure the .30 and 35 make the feathers fly but the .25 is perfect for me all around. Not to tiny to load in mags, bucks the wind great , and not to terribly expensive to shoot and a good compromise between them all.