Yeah, there are a few other guys I think are really great, but even Mirko wasn't as dominant as Aerts was. Mirko just had the one-shot style that made it easier for him to transition to MMA, as opposed to Aerts' combos that opponents would probably have used to shoot on him.
Aerts, in my opinion, is the best kickboxer of all time. Hoost runs a close second, and Mirko behind Hoost. I also think that there are some great guys like Branko Cikatic and Musashi who don't get all of the credit they deserve, but they're not up there with those three.
Im not arguing that, I know Aerts is much better than Mirko, But I really like Mirko's style, its pretty predicatble but hes just so fast and effective.
Aerts was probably the most laid back dude in K-1, he just sat back, set up his shot with a couple of punches, got close and wrapped that leg around the back of your head, he was almost all shin, while Mirko was mostly instep.
Andy Hug was also an amazing dude, he had so much creativity and was always exciting.
But I have to put Aerts at #1 for being the first king of the HK, then its almost a draw for 2nd between Mirko and Hug.