Lake Taghkanic is high among my favorite state parks. I've been there both camping and on day trips. The campsites are your typical New York State setup— a picnic table, a fire ring, and a flat place to put a tent, with access to toilets and showers. Try to avoid the platform and tent sites in the inner loop if you want any semblance of privacy. The beach is man-made and well-maintained with four swimming sections, each with their own lifeguard and a nearby playground for ages 3-12. Bring your fishing gear if that's your thing, your hiking bootsfor the many marked trails, or a good book and a chair.
Day use is $10/car, camping starts at $27/night for a basic tent site.
You can't go wrong here on a sunny day. Having said that, I have been twice, and the park was at capacity. You may want to keep that in mind, if it's a really, really nice day.