After a visit to Canada's Wonderland, I can update my list!
1. Cedar Point - My home park since I was born! The great coasters are supported by a good amount of fun flat rides, and the park layout (for me) is very simple and easy to learn for first time visitors! My favorite park overall.
2. Kings Island - A great park with great coasters, and great halloween and winter events as well! My main complaints, however, are the lack of shade and lack of flat rides. That being said, Drop Tower is very fun!
3. Kings Dominion - A very pretty, scenic (at times), and great park! However, outside of the top 3 (Twisted Timbers, Dominator, I305 for me, in that order), there isn't really anything worth riding more than once. The closest thing I'd say is even close to worth re-riding would be Flight of Fear, which is fun, but not really mind blowing. And yes, I said Dominator was better than I305.
4. Carowinds - Kings Dominion and Carowinds are very close in terms of my rankings. The only 2 things that I would consider worse than Kings Dominon are the significantly less shade (park-wide, that is. There are some spots that are more shaded), and even LESS coasters worth reriding. Afterburn and Fury 325 were the only 2 stand-out rides, but there I was also surprised by a few of the rides. PvZ Arena was really fun, even when there weren't many people on the ride, and Hurler and Nighthawk both exceeded my expectations, being much smoother/not as painful as I was expecting. Drop Tower is pretty fun, and was my first Intamin drop tower, and Fury was amazing, but I never got a back row ride on it. I really have to go back to here and KD!
5. Canada's Wonderland - A great park! I didn't do the family area but I saw it and it looked HUGE! The flats are some of my favorite I have ridden as well. If there was one thing that I think needs to be there, it would be *less* coasters. I felt that there were too many "filler" coasters and not enough true quality rides. But the big 3 are very great and I had a lot of fun overall! It's very pretty in places as well.
6. Michigan's Adventure - It's a great family park, but that's about it. Mad Mouse and Shivering Timbers are great, the former even making my top 15, but overall, it's just not worth the 4 hour drive north.
I have been to Dorney Park, but it's been too long (around when I was 6 or 7) since I've been back, so I don't think should rate it fairly. I do remember it having a good rapids ride, Apollo was fun, and it was good overall. This should be updated by the end of July!