1) Rick Rude- although some consider WCW International Title to be a World Title. I don't
2) Ted Dibiase- he had the belt in his hands, but is not considered to have been champion. Sorry Macho, he should have won at Mania IV.
3) Scott Hall/Razor Ramon- Absolutely dominant in the 90's, probably would have been World champion had he stuck around WWE instead of jumping to WCW. Instead he became part of the biggest angle in pro wrestling history.
A side note, Curt Hennig was AWA World Champion. That was a recognized World Title, and more relevant than any of you ware giving credit.