Dynaman! How could anyone not list that? With great action and explosions and that awesome theme!
Changeman. Guns, guns, guns.
Flashman. I like how it's synched with the music, too.
Maskman
Turboranger. Similar to Flashman.
Carranger (second credits). I love when the actors are lined up with their in-suit counterpart and when Minoru falls down giving out his meishi...
GoGoFive. Our heroes are earnin' their money! And Shinichi Ishihara rules.
Kamen Rider Kuuga (final credits). Kuuga had so many cheesy credits that when the show was almost over they finally got some decent ones. I like the one that starts with Godai standing, handcuffed by a ring of light...
Kamen Rider Agito (first credits). I love that part where Hikawa is running in between Ozawa and Houjou and the next shot is G3 riding in between them. Those second OP credits are crap, though.
Kamen Rider Ryuki
Kamen Rider Faiz (for the Orphenoch stuff).
Kamen Rider Blade (second credits -- I think almost more creative than the show during its entire run. Those first bland credits suited the show well).
Kamen Rider Hibiki
Spielban -- I love these credits, especially the shot of Spielban and Diana walking in front of the sun, with the next shot being them in-suit. This song's my favorite Ichiro Mizuki song of all-time, too.
Jiraiya -- Watch this show and learn how to be real ninjas, Kakuranger and Hurricanger!
Zubat -- Great song, great credits, GREAT MIYAUCHI. "Asuka!!!"