Gosh, this is like asking me to pick which one of my kids I like the best. I love them all!
We used to always request the 1400 loop. Specifically, the kids loved the sites which back up to the campfire area. I'm sure a lot of folks would not like this, but it is fun! I also agree with the person above about the inner loop (Little Bear) we camped on it a lot, and love the set-up.
We have stayed on the 300 loop a couple of times. There are some nice sites on there, but we kind of got small ones both times, and felt crowded in.
For Spring Break 2006, we were on the 800 loop. Loved it. We have requested this loop the last few times we camped, and loved it, except for our most recent visit. I apologize to the pet lovers for what I am about to say, but on our last trip (in March of '07), we had a site (854) toward the end of the loop. We were surrounded with folks with dogs. The people camping across from us had a little dog that would not stop barking- even when they yelled at the top of their lungs "SHUT UP!", and trust me, they did that a lot. That little dog just stood inside the screen door of the trailer all day and all night, and barked up a storm whenever anyone walked by. That thing gave me a headache! Then, one of our neighbors to the side had a cocker spaniel that they locked in their trailer all day, and that poor thing barked from the moment they left early in the am until they came back from the parks at night. The thing literally never stopped! You would think he would take a nap or something, but never! At least his barking was muffled, but it was still annoying. So, I am not sure about pet loops anymore. The problem with that is that there aren't many non-pet loops left. This really is the only time that we had this kind of experience. The folks who were camped closest to us on the other side had a big golden retriever, and he was a great dog. Never made a sound. They didn't even have him on a leash or chain, and he stayed right there with them.
For Thanksgiving 2006, we were not able to get ressies for a preferred loop, and ended up on the 1000 loop. That loop was wonderful. The sites are big and far apart (at least after the first few in the loop). That is a nice loop. We might try it again.
We have camped on the 200 loop only once. It is a great location, but the sites seem cramped.
We have camped in 900 a couple of times- like it too.
TCD