Oooh, controversial ground...
Dog parks are another one of those things: you either love 'em or hate 'em. There are no dog parks in the town I live now, but when I was in Austin, I took my dog to the dog park near my aparment all the time. I personally never had any bad experiences: in fact, both my dog and I loved it. It's probably best to break it up into pros and cons.
Pros:
-Great place to socialize if you have a friendly dog.
-Wonderful place to meet and chat with other dog owners.
-If it's a good-sized park, your dog will get much more exercise than by just walking on a leash.
-Some dog parks have agility courses, pools, etc., right inside the park. It makes it a great place to work on training or just to run amok with your pooch.
-Most friendly dogs absolutely adore the dog park, and tend to make "best friends" with dogs who are usually in the park at the same time.
Cons:
-Run the risk of exposing your dog to viruses, diseases, fleas, ticks, etc.
-Just because a dog's at the dog park doesn't mean it's friendly. I once saw a dog owner bring a terrier that tried to attack every dog in sight.
-Your dog might love 99.99% of all the dogs you meet, but there's always the risk you'll run into that 0.01% dog that yours ends up fighting with.
-Don't even think about bringing a female in heat or a very alpha dog to a dog park.
All in all, I think it's up to you. If you choose to go, I'd initially go during a time of day that's not very crowded. Keep your baby on a leash until he meets all the dogs, and you're sure they'll be friendly.