You are all forgeting BTAS. In the episode birds of a feather (ep. 52) He get's bailed out of prison, falls in love, and beats the living spit out of some gangsters. He didnt use the gadgets in his umbrellas. His origin is like the ultamite misunderstood character, and some of us can relate in some way to it. Plus he is the only succesful villian in Gotham that Batman can't get to. Gotta say he is the best. After all, he runs gothams underworld. He is short fat and has a small obsession of birds.
Making him more threatening. He has an arsenal of umbrellas, hes fat, short and ugly. Yet he's the top mafia leader and one of the most threatening in Gotham city! (not nearly as threataning as The Joker, of coarse)
Plus he can hold his own, as portraid in the episode of BTAS birds of a feather. Protecting Veronica, he beats down some gangsters.
"I've said it a billion times. A villian's quality is not measured by his power level. Penguin is a clown too, but at least he's got real depth as a character. Spidey's villians are all the same guy with a different power."
Plus Penguin is the only one in gotham with a succesful career as a criminal, and batman can't do anything!
ROGUES ALL THE WAY OBVIOUSLY. Weather Wizard would fight storm, in which i say is even. Then Abra would come behind storm and take her down. meanwhile, Trickster is on air, Black panther is jumping up at him cause hes calling storm a slut, then he would whip out a yoyo, and slice his face in half. cyclops shoots at mirror master, and he holds up a mirror portal, making it just get sucked into the void. then cap. boomerang throws an electricity boomerang, nocking him out, then captain cold freezes the body's, breaks them and lets the sun do the rest..