Hmmm... I can't really think up any coaster that (consistently) gave me blackouts. I305, All the B&M Batmans, Titan, the Superman coasters. I think only the coaster that would come the closest would be Typhoon at Bobbejaanland. On a rare occassion I get a blurry vision after the loop.
Could be that I'm getting used to riding forcefull coasters? Kumba, Dragon Khan and Maverick are a few of my favorites for example.