Well, I grew up in Salisbury MD (that someone already mentioned), this is 30 miles from Ocean City, so I am very familiar with OC. I actually avoided OC during the summer, other than when I worked there. I usually went before Memorial Day and after Labor Day. The worst part of OC is the congestion on 113 or Rt 50 getting there, although this is better since the completion of the bypass around Salisbury.
As someone mentioned, it is expensive and crowded. I was surprised that someone mentioned how clean it was, but maybe they are actually talking about the beach and not the city itself. The beach is very clean, but in the summer, the city is usually problematic with trash.
There is the beautiful Assateague Island National Seashore not far from Ocean City, unspoiled for the most part, not commercialized, and it has the wild ponies roaming free. Just remember not to get too close. I've seen a few people who didn't know any better or couldn't be told anything carried into the ocean by the seat of their pants or ending up with nice horsebites. You also need to bring the Off, as depending on the wind (land or sea breeze), the horseflies can be a problem.
And if you are going for crabs, take the 40 minute drive to Delmar, MD and go to the Old Mill. It beats Hooper's all the way around. Just plan on getting there early or plan on a wait. The Old Mill is all you can eat fried chicken, steamed crabs, clam and shrimp strips, corn on the cob, and hushpuppies.
Darn, now I'm getting homesick!