I highly recommend Kings Island. I've been there three times and love the park. Diamondback looks amazing! Also, I am a huge fan of the beast. If you ever have the chance, ride it at night and after a major rain storm. Due to the use of skid brakes, only one train can be run after a large amount of rain. This means they turn the mid-course trim brakes off! SoB is still very rough but not nearly as painful as it used to be.
Canada's Wonderland is fun too, but it has a somewhat questionable coaster line up, other than Behemoth, of course. By the way, Behemoth is amazing! Loading times are much quicker than average at CW because they reward their ride teams for achieving as close to max. capacity as possible. (The fly and sidewinder are exceptions for obvious reasons.)