Hi!
I live about 20 miles from the "shore" towns and have to say that Ocean City is my favorite, especially the southern end which tends to be a little more quiet. If you have kids, there's a boardwalk on the northern end with amusements, food, etc., and the beaches are very nice. It's also a dry town, so there's no nightlife or rowdiness going on.
Townsends Inlet, which is the southern end of Sea Isle City, is also very nice, as is Avalon.
I've been to Cape May (which is a beautiful town), but never to the beach so I don't want to comment on that!
I agree with the Wildwood comment. It can be a really rough town and their beaches are very large, so depending on where you are, you really have a hike to the water!
Wherever you decide, have a great time!
Michele