Realistically, just about everything being made today will be squirrel hunting accurate. They all have pluses and minuses from there.
For a semi-auto, the old standby of the Ruger 10/22 and Marlin 60 are both great choices. The 60 is a rifle you buy and shoot, the 10/22 is one you buy, shoot, and then debate what you want to personalize/upgrade/change. In stock form the 10/22 and model 60 will be more than hunting accurate.
For a new bolt rifle, it's hard to go wrong with the more basic Savage Mk II options. When you get into the more expensive models you quickly get close to CZ 452/455 price range, in which I'd take the CZ. The CZ line is a great value for a well built rifle. Plenty of other good new rifles built but those two get the most attention.
The used market is another great way to go. Many of the old Remington, Winchester, and Savage models will shoot a treat and are built with a care that isn't available in many rifles today. They may have a few dents and dings and a trigger that's a little heavier than some of the target models available today but overall the value is outstanding for used rimfires.
I don't think there are many bad options today. Find one you like and buy it.