Blankets Creek is one of the premiere mountain bike trail systems in the Atlanta Metro Area. While perhaps not technically in the metro area (depends who you ask), this Woodstock trail is close enough to the city to draw a flood of riders up here every day of the week.
Thanks to the popularity, SORBA Woodstock has recently been able to vastly expand the parking area and add new trailhead facilities, such as flush toilets.
As for the trails themselves, Blankets Creek is an excellent example of a stacked-loop trail system. Short, flat, easy trails are accessible right from the parking lot for beginner riders, but keep heading further in and you'll experience intermediate singletrack as well as advanced trails full of rocks, jumps, berms, and some serious exposure.
While Blankets is definitely busy and can get crowded sometimes, the reputation and the popularity has been well-earned. Directional travel (depending on day) helps keep the trails from feeling too congested once you get away from the parking lot, so if you have never ridden at Blankets Creek before, be sure to carve time out of your schedule to do so!