We've been staying at San Clemente State Beach for more than 30 years now, and it's always an enjoyable time. The beach is great for surfing and boogie boarding, with the famous Trestles surfing spot located about 2 miles away. 

San Clemente State Beach is a pretty large campground with lots of commotion/activity, so if you're looking for peace and quiet, this isn't the place to go. Another thing to consider is that the beach is a bit of a trek, especially if you're carrying a bunch of coolers, chairs, umbrellas and boogie boards. Still, once you get down there, it's a great beach and very beautiful. 

If you want to go shopping, there's a Rip Curl outlet nearby that has a lot of good deals on surf clothes, supplies, etc. The Pier is about a 10 minute drive away, where you'll find several decent seafood restaurants.