This one could have the most discussion, or it could be a complete bust. Even before the "Invasion", there was a number of guys that left WCW for the Attitude that was the WWE. Who do you think did the best at crossing over?
My choice, Booker T, made the biggest crossover, and is still using the push now, in TNA. He is the only member of WCW to win the WWE Title after the invasion, and is the only one still at the top of the card of his company. His gimmicks may not have been the best, but they kept him on top, and got him a ton of heel heat. He even teamed with Goldust for a run with the tag titles.
My choice, Booker T, made the biggest crossover, and is still using the push now, in TNA. He is the only member of WCW to win the WWE Title after the invasion, and is the only one still at the top of the card of his company. His gimmicks may not have been the best, but they kept him on top, and got him a ton of heel heat. He even teamed with Goldust for a run with the tag titles.