I'm not clear if you're looking for a "traditional" optical scope, or a red dot.
I like a quality 2X pistol scope. I happen to have found a good deal on a Leupold, but there are many other quality scopes out there. A good 2X scope with a duplex or fine wire reticle should give you a nice crisp sight picture, capable of the precision you'll want for hunting.
Higher magnification is pretty hard to hold still, unless you're rested on something. I suppose a guy could get something like a 2-6X, but I bet you'll find yourself using it on the lower end of the magnification range when using it for plinking and squirrel hunting.
Another option is a "red dot" scope. I've had a couple of UltraDot 25 scopes, and think quite a bit of them. One is from the late 80's, one is from the early 90's. They've been a good investment.
A red dot will speed up target acquisition, but will most likely be less precise for squirrel hunting. You'll want something with a small dot size, like 2MOA. A 4MOA red dot will cover about an inch at 25 yards, so head shots on squirrels can get kind of dicey at longer distances.
Do a few searches here, and you should find some more answers.
Happy shopping!
