For me, the .22 caliber strikes a good balance. The pellets are large enough to handle, large enough to see on my targets (I'm an old guy), and provide enough power to take most pests.
Most of the rifles I've had are in the medium price range. Of these, the Wildcat III compact is my overall favorite; my go-to gun. Easy to carry--short and light--so good for hunting, and not bad on the backyard bench.