Who but Weather Wizard could challenge the combined might of Superman and the Quik Bunny?

But seriously, One of the things that makes Mark (or Marco, in the New 52) Mardon such a great villain is his crossover appeal. His weather manipulation abilities make him one of the most powerful Rogues, and having challenged at least three Flashes - even playing a part in the death of Bart Allen - he's also proven his chops in ways few others have. But he's also challenged Superman, the Justice League, and served on numerous villain teams, making him not just a great Flash villain, but a great villain all around. In fact, he's so great, he was the first villain The CW went to - he's the main antagonist of the pilot episode.