If you are willing to drive just a bit, Colonel Beatty just outside of Matthews is pleasent. Also just beyond Waxhaw there is Cane Creek Park, a pretty good size lake and plenty of shoreline spots. There is also a county park right down on Lake Wiley where you can fish from the pier or the shoreline.
Fishing (http://www.charmeck.org/Departments/Park+and+Rec/Inside+The+Department/Divisions/Stewardship+Services/Fishing.htm - broken link)
Cane Creek Park