Obviously, big, secluded sites are always a good thing. However, for us, it depends a bit on why we're camping at a particular place.  Our trips usually fall into one of three categories:

[li]Destination - Our camper is usually just a mobile hotel room for us.  We tend to spend most of our time elsewhere, and only sleep in the camper.  Good examples of this type are Niagara Falls or amusement parks.  Our primary concerns are proximity to our destination and it's relatively quiet at night so we can get a good night's rest.  [/li]
[li]Recreation - We're there to do some hiking, kayaking, swimming or other outdoor activity at or near the campground.  We'll likely spend some time at our site, but the primary purpose of the trip will be the activities.  Primary concerns here are similar to the Destination type trips, but with a little more focus on bigger sites and privacy since we'll be spending a little time at the site.[/li]
[li]Pure Camping - The main goal for the weekend is to camp, maybe do a little hiking, sit by the fire, and relax.  Big, private sites with good facilities are the primary concern.  [/li]