I'd list Batman as first and Superman as second. I think Batman and Superman are the only DC heroes with really great rogues galleries. I know people like Flash's a lot, but I never saw anything there that really hooked me. Green Lantern has a few great ones, like Sinestro, Krona, and Manhunters, but all the others are lame, like Goldface, or too derivative and redundant, like the emotional spectrum characters.

Most of the other DC heroes have only one villain that is any good, like Black Manta or Black Adam, if even that.