Though I've ridden many coasters, I've probably ridden The Great American Scream Machine at Six Flags Over Georgia more than any other. It was the first "real" coaster I ever rode*, and have ridden it hundreds of times since!
* The Dahlonega Mine Train was the actual first coaster I rode, but it doesn't really count. LOL!
I ride Kraken around eight times every time I visit Sea World, it's sort of a tradition for me, and I've been to Sea World... around twelve times. So I've probably ridden Kraken around 96 times. But then again, I went way more then eight times the first day, so that isn't entirely accurate.
It would have to be the Demon at CGA, simply because of proximity and longevity. I wouldn't even hazard a number, I've been riding it since the park opened and it was called The Turn of the Century featuring only two bunny hops and a corkscrew. Tidal Wave might have it beat though, certainly if they hadn't removed it, because it was an adrenaline rush and NEVER had a line even when the park was packed the last decade or so.
I'd imagine Flight Deck will eventually overcome them both as I'm being more selective now and don't get to Marine World nearly as much as I'd like. The Giant Dipper in Santa Cruz and Thunder Mountain DL also come in fairly high.
Be sure you're not looking in a mirror before you start pointing fingers.
Colossus at Thopre Park. Only about 20 or 25, but I am soooooooo bored of it now. It's a pretty slow ride and headache inducing ride anyway so next time I go there I'll focus on Stealth and Saw The Ride instead.
Mine is actually Dominator/Batman Knight Flight. When it was over at Geauga Lake and Built for the 2000 Season, I had a season pass. Went every single day of the season (because I had nothing else to do) and I rode it at least twice when I went. On the slower days upwards of about 10-15 times. This is not counting the other few times I went and rode it laster during its time there. It has probably been a few hundred times, I didn't really keep count.
This year I've been to Kings Island 5 times. I rode Diamondback 3,5,7,10 & 20 times respectively. That's 45 times so far. I plan on going back in October to at least make it 50.
All coasters of the Phantasialand, like Black Mamba and Colorado Adventure. 2 seasons and ridden so many times each visit. And this year i wasn't there because it's just boring after two complete seasons.